Just announced that "Don't Stop" and "World Turning" will be available next Tuesday for download for "Rock Band".
Personally I think "Don't Stop" is a poor choice because it doesn't really seem the type of song that'd be a blast to play (repetitive drums, etc.) but it's a good party-song choice that everyone will know.
"World Turning"? Brilliant. They went with one that not everyone would know and the guitar part is going to be fun and challenging for those who play on expert. Could turn a lot of new people onto the band!
I'm still rooting for "The Chain", which seems to me would be the best song in the Mac catalog for the game, but this is good nonetheless!
http://www.rbdlc.com/news/?p=2715