Here's a few that I particularly like...
http://ichigos.com/They've got a TON of music from anime, mostly for piano, but some for other instruments, and even a few for small ensemble.
http://pianosquall.com/This guy (Piano Squall) arranges video game and anime music for the piano. His music is a little more difficult than the ones you usually find online by amatuer arrangers, but after some practicing it sounds really awesome.
http://www.finalfantasymusicscores.com/If you're a Final Fantasy fan, this is a must-see. They've got probably over a hundred arrangements for solo, full symphony, and everything in between.
I had some links to movie music too, but that was before I lost my bookmarks... Anyway, I hope that helped!
smile