It wont be completely nationwide by the end of the year.
It'll be more available - but generally only in areas that have enough potential customers to make the investment worthwhile.
BT's Vision is likely to have the largest footprint - but that's not showing broadcast channels via broadband. That's a freeview box with an extra 'on demand' bit so that you can access films and sporting event etc a bit like Telewest's Teleport and the *original* Homechoice service.
Sky will be announcing their broadband intentions over the summer - but that's likely to be normal Sky (i.e. satelite) with an extra broadband net connection thrown in and Wanadoo's 'Live' box is meant to also be being developed to offer VOD stuff (although Wanadoo's just in the process of being swallowed by Orange so a lot of their plans may be a bit screwed right now).
Basically, if you're area is already covered by an LLU provider like Easynet or Bulldog then there's a good chance that you're in an area where other providers will also install their kit - check your area at
http://www.samknows.com - do an exchange or phonenumber search and see if you've got an 'Local Loop unbundling presence' providers. The more you've got, the better.