Until AM - DJ in your browser with this SoundCloud music mixer
Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.
Songlio - Free musical guessing game: race friends to name that tune
cassini - Polyphonic Synthesizer for iPhone/iPod touch
Fretello Stage - Jam, record and share your music in the blink of an eye
zMors Modular - Full featured modular synthesizer for iOS