ABC has finally taken NBC's lead by posting its TV shows free of charge for streaming video. I used NBC's Heroes links to get caught up on episodes I missed this season, and now it has become my favorite show (probably tied with Battlestar Galactica).
Unfortunately for those not caught up on Heroes, they look like they have removed all of the first half of the season from posting. The reason is probably that they'll be on DVD shortly. However, they have compensated by providing cast commentaries for this year's episodes. Fun.
I don't know what that will do for the iTunes market, but it certainly has made it a lot easier to (a) not have to bother with taping episodes and (b) take it to the next level with web surfing.