Maybe I got really lucky but I frequent the help wanted section of this site as well as iphonedevsdk.com and found a few composers willing to do original music for my game. It has worked out really well so far. (you can't have my guy though) Just ask if anybody has any original tracks that they'd like to feature on your game. I'm sure a few composers might take the opportunity to beef up their resume.
My recommendation would be http://www.stockmusic.net/, their musics are really great and you can choose anything and try it on your games.
music packs I put a few music packs on my site, 4 so far. http://www.honeytribestudios.com/game-music
Go to musicians music forum and get in touch with some of them. You will find probably quality and free help for your projects.
