BBC & Channel 4 have also signed up for Windows Media distribution so I can't see there being any UK TV content available through iTunes.
At least the BBC are bound by their charter and will have to pursue openly-accessible means in the long run; their ventures into YouTube show some of their intentions. Channel 4 also has a charter, but I'm not sure what requirements are laid upon them in this regard... Channel 4 isn't much of a producer these days, anyway, preferring to rely on independent producers or commissioning where necessary.
What Apple need to do is to pursue partnerships where they might not necessarily have the upper hand... something which I understand they're not inclined to do, which is shortsighted in my view. Still, what do I know?