Software for composing iPhone game background music

I want to compose some basic background music for an iPhone game. What's a good program for OS X (10.5.8)? I'd like to save the audio files in a compressed format that'开发者_开发问答s compatible w/ AVAudioPlayer (aif, aiff, caf, mp3, aac, m4a, mp4, wav).

Perhaps something like Logic Studio Express?

Cheers!

Logic Studio Express is definitely a good option. It is loaded with features, and actually developed by Apple IIRC.
You could also try Reason, if that is the sort of thing you are looking for.