Once upon a time, not long ago, there was a cool little site called RaiClick, from which you could watch RAI's TV programs from your computer. This has now been replaced by the newish site Rai.tv. It's been revamped to be very Web 2.0 and seems to have been influenced by You Tube. It even has a "community" feature (or as the Italians say, "la community"), search functions, listings in order of popularity and so on.
The home page also cleverly functions as an intelligence test. Here's your little cheat sheet: go to diretta TV, and you'll see what looks like a remote control. Use this to navigate among the various channels (some of which will be blocked if you're not in Italy). Once you are in a channel e.g sports, you'll have a scroll-down menu. There is a volume button beneath the remote, to the left. To its right there is a button for Full Screen (press Esc to exit full screen).
Play around with it and give it some time, there's some worthwhile material there. And all free.