"There's an active project called iPhone Linux that is still in the very early stages of development. They have a great goal of someday creating an open source operating system that can be a feasible competitor to the existing iPhone OS. They are also planning on collaborating with Android, OpenMoko, and Ubuntu Mobile. I'm sure one of the trickiest parts of development would be creating several iPhone specific drivers for display, multitouch, wi-fi, accelerometer, sound, baseband, and so on, so I wish them luck."
