Harmonix has released the DLC list for Rock Band for the week of May 13:
The DLC for next week is $1.99 (160 Microsoft Points). It appears on Tuesdays on the Xbox 360 and Thursdays on PS3.
Hanging on the Telephone by Blondie (master)
Train in Vain by The Clash (master)
Kool Thing by Sonic Youth (master)"