Use Nintendo Wii remotes on your Mac. Simply.
Wiiji is the perfect joystick solution for Wii remotes on Mac.
With Wiiji, your Wii remotes will appear as ordinary joysticks to any application that supports joystick input. It does this through a kernel extention.
If your favorite game doesn't support joysticks, Wiiji can emulate keyboard input, too.
It runs conveniently in your menu bar.