Alright, I know this is a little late, but better late then never. No one seems to be posting the Rock Band DLC anymore, so I'll be the guy who does the job. Please note that I will post the DLC on the day it comes out, as the xbox.com Marketplace section no longer has a "Upcoming Rock Band DLC" section.

Children of Bodom - "Are You Dead Yet?" -- 80MSP.
Finley - "Tutto e Possibile" -- 80MSP
Platero Y Tu - "Hay Poco Rock & Roll" -- 80MSP
Squeeze - "Tempted" -- 80MSP
Tokio Hotel - "Ready, Set, Go!" -- 80MSP
All American Rejects - "Real World" -- 80MSP

Naked Brothers Band - "I Don't Want to Go to School" -- 80MSP
Naked Brothers Band - "Body I Occupy" -- 80MSP

Miranda Cosgrove - "Headphones On" -- 0MSP

Well I guess Harmonix has to appeal to the 8 year olds some how...

For videos of Guitar, Bass, and Drum charts of most of the DLC, please visit the following Youtuber's Channels:

http://www.youtube.com/user/Npeaen -- Guitar Charts (Expert)
http://www.youtube.com/user/S1ckH4ndsBass -- Bass Charts (Expert)
http://www.youtube.com/user/Jarr3tt88 -- Drum Charts (Expert)