http://investor.activision.com/releasedetail.cfm?ReleaseID=307978 Supermassive Black Hole, Stockholm Syndrome and Exo-Politics are being released as Guitar Hero III DLC on Thursday. Additionally, rumor has it that Hysteria will be released for Rock Band DLC later this month.
Oh man, I wish it was for RB, but this is still cool. I've been craving Stockholm Syndrome forever. Hysteria is being released in the UK on the Rock Band, and will eventually make it over to the US.