TwitPaint lets you paint graffiti and post it on Twitter.
Make graffiti in 140 strokes or less and share with your followers.
Your followers can remix and update your work by doing the same thing with a reply @you.
Expand your definition of graffiti art: play board games, brainstorm, or paint the next Mona lisa with your friends.
TwitPaint lets you sign in with your existing Twitter account or you can create one for free at twitter.com.

Paint on iPhone 3.0