ABC, NBC and CBS have recently blocked access for users who wanted to see their shows using Google TV. Google is now trying to negotiate with these networks and convince them to unblock their access.
Google TV is not much different then connecting your PC to a TV, which you can already do to watch those network's content from the web. They are offering their content on the web so it's perfectly fine to see it there, except they actually don't want you to use your TV to see it.
Right now, they think of the web access to their shows as "complementary" to their TV access, so the moment the web content starts replacing their TV content, they become worried, because they get paid a lot more for advertising run on TV than they get paid for advertising that runs on their websites. They don't want to lose their big revenues.
In a way that's understandable, however, they need to realize that watching content through the web is the future, and they can only fight the future for so long. Instead of trying to fight it, which should be their default action, they should try to embrace it and see how they could make money from it.
Google can help them make money through Google TV by offering them the tools to know exactly what kind of audience is watching their shows, and offer very targeted ads, compared to the ones running on TV right now.