“We are looking carefully at the DS, and certainly aren’t ruling out developing for it in the future. However, for right now, our focus is on Rock Band Unplugged as a PSP title.” - Greg LoPiccolo, VP of product development at Harmonix

Link

i bet it will be on the ds one day, im surprised it hasnt with guitar hero ds becoming a big hit

lol and John Keller continues to get owned

I still don't understand how Rock Band on the PSP can work. At least all Harmonix has to do on the DS is make a game and have it set to read the Guitar Hero grip. There is no touch screen to strum on the PSP. It doesn't look likely a large peripheral can be attached to the device. I'm really intrigued with whatever they have planned because I just can't see it being feasible at this point in time.

It'll either be button pressing while holding the PSP on it's side or it's being developed for that rumored PSP2

from kotaku

"the peripheral-free game as a beat-matching rhythm title that uses the PSP's directional pad and buttons to play along with guitar, bass, drum and vocal tracks"

http://kotaku.com/5159653/rock-band-psp-first-details-its-amplitude

OK so it's innovative than I thought it'd be :P

It'll bomb.. Giving you Rock Band: Taking the fun out of pretending to play the instruments! PSP Edition!

It might not be so bad actually. It could be the spiritual sequel to Amplitude i've wanted for years. Harmonix's original game, Ampitude (well, Frequency, which was the one before Amplitude if you want to be pedantic) was about beat-matching.

Haha, you wish. It will also be a part of a new PSP Entertainment Pack - along with 4GB memory card, and some other stuff.