Several sites on the web (The Other Mac Blog, MacRumors) noted that CBS.com had posted some iPad test videos. At first glance you might be confused as they show up in a standard Flash player, but MacRumors did some further digging and uncovered some HTML5 code and WebKit references.
CBS.com is apparently readying itself to take on the iPad, Apple's upcoming (and questionable from many viewpoints) touch screen tablet, which of course has no Flash support. As the struggle continues over the HTML 5 framework and codecs for the <video> tag CBS seems to be now set to enter the fray. If they are working on supporting the iPad with HTML 5 then you can bet they're going to use H.264 to video encoding.
They are using a standard fallback mechanism so that if you visit in a standard web browser, even one that supports HTML5, you will see the Flash player. But the CSS shows some of the references that MacRumors spoke about.
The webkit references at the bottom reference the mobile Safari browser engine. Not being a member of the iPhone developer community I did not have access to the SDK and iPad simulator so I couldn't investigate further.
It's obvious that CBS sees some value in trying to get its videos onto the newest Apple platform and while the other majors might, they have not been so open about it.
Now this doesn't necessarily mean that CBS is openly supporting H.264 or anything else. I think it only truly shows that they believe catering to the iPad audience is worth some testing and time. That means they think it's valuable and could be worth the expenditure in some R&D.