Spawn Illuminati by Elements of Design is an iPhone and iPod touch beauty. Even though Spawn Illuminati serves no other purpose than entertainment it still creates some rich effects that can be controlled and altered with your fingers.
iPhone and iPad apps tagged "art app."
Flipbook is Fun for all Skill Levels
Flipbook is a fun app that is much more sophisticated than it lets on. For an iPhone app with such a low price, Flipbook contains an incredible level of features -- color and brush size controls, layers and onion-skinning, undo, the ability to load pics from and save images to your photo library. These are robust tools.
Kaleidoscope is a Gorgeous Adaptation of the Original Toy
If you like to look at pretty things you could go out and get yourself a collector's edition kaleidoscope for around a thousand bucks. Or you could buy Kaleidoscope for $1.99 and use the rest of the money to frame your fancy new artwork.