The idea is to protect cable subscription revenues by giving pay TV customers–but only pay TV customers–Web access to all the shows they get on TV, and hoping this keeps them from canceling their subscriptions.

But that’s old news: Comcast (CMCSA) already told Bloomberg earlier this month that the two companies are linking up, and that Time Warner (TWX) would offer programming from some of its networks in the first part of Comcast’s tests.

Presumably Bewkes and Roberts will offer up a few more details, like which Time Warner networks are participating (good bet: TNT and/or TBS), along with a timetable. But I worry that the press conference will be light on details, in large part because many of the details haven’t been hammered out yet.

Still, I’ve been able to glean more from industry executives who’ve been involved in discussions with Time Warner, Comcast and other players in the authentication effort, which Bewkes has been calling “TV Everywhere” and Roberts has been calling “OnDemand Online.” Some of the details:

• The test will start very small–with some 5,000 subscribers–but Comcast is determined to expand it aggressively and wants to have it available throughout its system by the end of the year. Comcast plans to use its Fancast video portal as a hub for its efforts. And it  may use other digital assets it has acquired as well. Online Rolodex Plaxo, for instance, which the company bought last year, could be used to help subscribers sign in to watch their shows.
• The test is separate from Time Warner Cable’s (TWC) own authentication offering, which is essentially the same thing but will launch later than the Comcast test, using different technology, and will likely offer a different mix of programming.
• And those tests are separate from the one that telcos Verizon (VZ) and AT&T (T) have been working on with satellite operators Echostar (SATS) and DirecTV (DTV). That one also has the same thrust, but will take the longest to roll out.
• Comcast isn’t likely to announce other programming partners for the tests until later this month.
• Hulu is interested in playing along, because its owners–GE’s (GE) NBC, News Corp.’s (NWS) Fox and Disney’s (DIS) ABC–see authentication as a way to appease riled-up cable providers. The cable guys are upset that Hulu shows (some) cable programs for free while they have to pay for the right to air them. In theory, authentication solves that problem for Hulu because everyone will be on a level playing field: Only cable subscribers will get access to cable programming, whether it’s on Hulu, Fancast or anywhere else. But the cable guys aren’t rushing to let Hulu in just yet.
• Separately, NBC has been talking about offering some cable programming that isn’t already on Hulu for the tests. That could also be seen as an appeasement move, but I’ve heard a more benign suggestion: NBC merely wants to figure out if authentication technology works because it is considering using it for some of its coverage of the Vancouver Olympics next year.
• CBS (CBS), which isn’t a part of Hulu and which doesn’t have any cable assets of its own, would still like to get into the mix. The idea is that the network would offer the cable guys shows that it has kept offline until now (say, “The Mentalist”) while tying the Web programming to “retransmission” fees it would like to extract from the cable companies for all of its shows. Comcast executives seem amenable to the notion.
• Big cable players like Viacom (VIA) and Liberty’s (LINTA) Discovery may participate in some trials but not others. Viacom, for instance, has been talking about working with the telco group but not with Comcast during the trials. It has also discussed offering a “premium product”–like access to the full “Spongebob Squarepants” library or other kids’ shows that have a very limited online profile–to Time Warner Cable subscribers for an additional fee.

Bewkes and Roberts are scheduled to speak at the Time Warner Center at 9:45 am EDT, so we’ll know more shortly.

The  TV advertising market is $70 billion, give or take a few billion. So when peeling off a few million dollars from that constitutes progress, you can see just how far Google (GOOG) has to go.

In fairness, Google’s TV business isn’t really designed to get ad commitments, at all–the whole idea is that advertisers can buy spots on the fly, the way they can with its core Web business. So this at least constitutes a willingness on the part of ad buyers to give the platform a shot.

But that platform is still pretty small after a couple years of work: Advertisers can use Google to reach viewers using Echostar’s (SATS) service, and some of GE’s (GE) NBC Universal cable networks, but that’s about it.

The program, created by Echostar’s (SATS) Sling group, is designed to let users watch TV shows, beamed from their own sets, on the  iPhone. It goes on sale for $29.99 today via Apple’s (AAPL) iTunes store–but without the ability to work over AT&T’s 3G network.

That’s our decision, says AT&T (T). The company’s rationale: The iPhone’s too powerful, and our network isn’t powerful enough.

That’s the gist of its argument, which both makes sense and confuses. AT&T says the Sling app could consume lots of network capacity, which is straightforward enough. But you can already use Sling apps for other handsets, like the BlackBerry, on AT&T.

The difference, AT&T says, is that the iPhone really isn’t a phone at all, but a PC that happens to make phone calls. “We consider smartphones like the iPhone to be personal computers in that they have the same hardware and software attributes as PCs.”

No argument there, either. But again, given that you can use the SlingPlayer over AT&T’s spectrum using different devices, it seems as if AT&T is really making a different argument: Just because you can watch TV on other devices doesn’t mean you will. But if we give people the chance to watch TV on iPhone, they’ll flock to it–and our network can’t handle that.

See for yourself. Here’s AT&T’s full statement, via Engadget:

Slingbox, which would use large amounts of wireless network capacity, could create congestion and potentially prevent other customers from using the network. The application does not run on our 3G wireless network. Applications like this, which redirect a TV signal to a personal computer, are specifically prohibited under our terms of service. We consider smartphones like the iPhone to be personal computers in that they have the same hardware and software attributes as PCs.

That said, we don’t restrict users from going to a Web site that lets them view videos. But what our terms and conditions prohibit is the transferring, or slinging, of a TV signal to their personal computer or smartphone.

The Slingbox application for the iPhone runs on WiFi. That’s good news for AT&T’s iPhone 3G customers, who get free WiFi access at our 20,000 owned and operated hot spots in the U.S., including Starbucks, McDonalds, Barnes & Noble, hotels, and airports. AT&T is the industry leader in WiFi.

[Image credit: Markhillary]

Brothers Blake and Jason Krikorian, CEO and SVP-business development, are out, effective immediately. Jason Hirschhorn, who runs the company’s Sling Media Entertainment unit, plans on staying through the end of February; Ben White, chief creative officer at the entertainment group, will stay on through Feb. 1.

Some background from paidContent’s Staci Kramer, who had the story first:

Also leaving: Greg Wilkes, VP-sales. I’ve been told COO John Gilmore will take the reins for now but that may not be official. While no one is talking about any differences, there certainly is a big cultural gap between the tech-creative side and the traditional cable team at EchoStar.”

To tease that out: The Sling team can rightly point to a string of successes–the company racked up a number of awards at both the Consumer Electronics Show and MacWorld last week–but if things were humming smoothly at Echostar, you’d think the company would find a way to make them stick around.

The Slingbox is a potentially disruptive technology, but it’s still nascent, and Sling.com just launched late last year and will need a motivated team to help it gain traction in a crowded field. All those involved say they’ll be taking time off; everyone who knows the team involved finds that hard to believe.

And who knows? Maybe John Chambers, Steve Ballmer and Brian Roberts will indeed say something important today and tomorrow at Quadrangle’s Foursquare conference. Chrysler’s Robert Nardelli is speaking too. He might have something newsworthy to say.

But you are unlikely to read about it.

That’s because there’s no press allowed at the private equity shop’s annual conference, which starts this afternoon at New York’s Plaza Hotel.

Or rather, there’s some press at the event. But they’ll be on stage. And they won’t be telling their readers and listeners what they saw and heard.

CNBC’s David Faber, Becky Quick and Maria Bartiromo, for instance, will be moderating panels over the next few days. So will the New York Times’ Andrew Ross Sorkin. And network TV news bigshots Katie Couric, George Stephanopoulos and Brian Williams will answer questions themselves (Portfolio’s Matt Cooper will be moderating that one).

Am I crabby because I asked (nicely) and couldn’t get in myself? Nah. It’s Quadrangle’s event, and they can run it any way they want. But it does look like a pretty good gathering of worthies. Maybe I’ll park myself in the Plaza’s lobby and see if I can bump into some of them.

Want to join me? Here’s the agenda for next two days:

Tuesday 11/11
2:00 PM WELCOME
Joshua L. Steiner (Quadrangle)

ONE ON ONE WITH JOHN CHAMBERS (Cisco)
Moderated by Jim Citrin (Spencer Stuart)

WHO DO YOU TRUST: INFORMATION AND NEWS IN AN  OPEN WORLD
Tom Glocer (Thomson Reuters), Nancy McKinstry (Wolters Kluwer) and Sheryl Sandberg (Facebook)
Moderated by David Faber (CNBC)

ALL ABOUT WIRELESS
Jean-Bernard Lévy (Vivendi), Naguib Sawiris (Orascom Telecom) and Ben Wolff (Clearwire)
Moderated by Steven Rattner

4:15 PM BREAK

GOING IT ALONE IN AN INTERCONNECTED WORLD
Philippe Dauman (Viacom), Charlie Ergen (EchoStar) and Robert Kotick (Activision)
Moderated by Becky Quick (CNBC)

GLOBAL E-COMMERCE: $500 BILLION AND GROWING
Barry Diller (IAC) and Hiroshi Mikitani (Rakuten)
Moderated by Steve Hasker (McKinsey)

6:15 PM COCKTAIL RECEPTION
Grand Ballroom Foyer
The Plaza

Wednesday 11/12
8:30 AM WELCOME
ONE ON ONE WITH STEVE BALLMER (Microsoft)
Moderated by Ken Auletta (The New Yorker)

INNOVATION AND THE NEXT BIG IDEA
Jean-François Decaux (JC Decaux) Robert Stephens (Geek Squad founder?) and Jim Wiatt (William Morris)
Moderated by Andrew Ross Sorkin (New York Times)

A CONVERSATION WITH SAM ZELL (Equity Group, Tribune Co.)
Moderated by Joanne Lipman (Portfolio)

10:00 AM BREAK

COOP-ER-TITION: A CONVERSATION WITH PETER CHERNIN (News Corp.) AND BRIAN ROBERTS (Comcast)
Moderated by Ken Auletta

REBUILDING A BRAND FROM THE TOP DOWN
Dan Hesse (Sprint) and Robert Nardelli (Chrysler)
Moderated by Maria Bartiromo

NOON Concluding Luncheon
CAMPAIGN 2008: IN FRONT OF THE CAMERA AND BEHIND THE SCENES
Katie Couric (CBS), George Stephanopoulos (ABC) and Brian Williams (NBC)
Moderated by Matt Cooper (Portfolio)

[Image Credit: PinkMoose]