Art is Open Source and FakePress just released Zones, a simple harmonic granular synthesizer for the iPhone. Create relaxing soundscapes and ephemeral melodies by creating grains with your fingers. Grains interact with each other establishing a musical force field. Best heard in headphones.
find out about it here:
Zones, simple harmonic granular synthesizer
or download it directly on iTunes
Zones is released for free with a Creative Commons Attribution-Share Alike 3.0 Unported License and the full sourcecode is available.