The busy beavers of the #iphone IRC channel, whose collective efforts have built the first unauthorized iPhone GUI application (it displays "Hello World" and does nothing else), have released the source for the demo app, buildable with the community-built toolchain and UIKit. There's also a compiled binary version of the app being hosted here.
Our collective hat is off to the dedicated hackers who are building a development environment for the iPhone from bits of string and folded-up tinfoil. It's an impressive achievement.
Thanks #iphone and Erica