This is the early stages of an iPhone visualizer I'm writing.
Screengrabs can be seen at flickr.com/photos/memotv/sets/72157612949492089/
(they look so much more aliased than they do on the iPhone screen, I should do some FSAA)
It was written with a custom version of openFrameworks (pre-006) and an early version of the ofxiPhone addon.
Information on openFrameworks and ofxiPhone at memo.tv/ofxiphone.