Just announced in the Stevenote here. Plus iTunes will be offering HD versions of many shows on Apple TV and for computers.
^It's just so you can carry on playing the episodes on your iPod/iPhone as they can't handle high definition video.
They're even offering some episodes for free! I downloaded BSG's "He That Believeth in Me" and it didn't cost me a thing! Yay!
More info here on which episodes: http://news.cnet.com/8301-13845_3-10039059-58.html?part=rss&subj=news&tag=2547-1_3-0-5 Also, I've noticed that there is a problem with the shopping cart method. In some cases it won't let you download the free episodes. Others have reported that they get the SD version, but not the HD one. Turning the cart off and using '1-click' solves both of these problems. I like the cart more than 1-click, but until I get these free episodes, I guess I'll leave it off.