There will be six new, full albums announced for the music game by the end of the August. One is a metal record, one is alternative, one is a pop album. We don't know which albums they'll be, though, but Harmonix is genuinely excited by the new content.
A new, full album will be out by the end of August. We don't know what yet, but we asked if it was Rush's Moving Pictures, and Drake would neither confirm nor deny it.
Steely Dan's "Bodhisattva," included with Rock Band 2, is destined to be the most difficult guitar song ever in the series. Drake said the guitar part is "mathematically possible" to play, but, as yet, no one has been able to score 100% on the song. We're sure the legion of Rock Band 2 players out there will take this as a challenge come the release of the game in October!
Harmonix plans to hit the 500 song mark for DLC by the end of the year.