The Skype guys are working on some set top box using the internet for video delivery.
They've had two hits so far: Kazaa and Skype, and they have some money behind them, so it could happen.
I can imagine a set top box that works a bit like BitTorrent to deliver content could work -- currently it takes quite a while to download an hour's worth of video , so you'd have to plan ahead, which isn't going to work well in our fast everything cultures.
If they can crack the delivery time it could happen. For that to happen we'd probably need an order of magnitude change in the speed of the internet in the last mile.
The BBC have been doing the "listen again" service for radio shows for a while now and are moving this same thing onto tv shows. Programs like Later ... with Jools Holland is available to watch online for a week after the show airs. Some shows are first on the minor BBC channels, eg BBC3, and online.
I think tv is already moving towards online program delivery. It is an easy prediction for Bill to make.
Mike