It was only a matter of time before the unbridled fandom of Nintendo and Apple transubstantiated into the ultimate hack.
In this clip, we see an OpenGL ES demo in which the Wiimote has been paired (over Bluetooth, of course) with the iPhone. The iPhone is then able to track the Wiimote's orientation in real time.
At the moment, this demo is nothing more than that—a taste of the Wiimote working on the iPhone. It'll be interesting to see if/how the project evolves from here. But imagine the potential of a game that used both the iPhone and Wiimote's accelerometers. Or heck, imagine playing a scaled down Wii Sports on your iPhone.