An enterprising Mac gamer (I thought they all dual booted to Windows?) created a USB driver for your Xbox 360 controllers to use on OS X. It's released under GPL, so if there are any problems you can go ahead and fix them yourself. Most things work, but there are still some items yet to be fixed:
- I don't think settings are persistent
- More settings, e.g. trigger deadzone, button remap
- Force feedback may elongate effects
- Force feedback (DirectInput-style interface) emulator may need more work
- Preference pane currently only tests rumble motors, by creating a force feedback interface but then just using the Escape functionality
- Driver needs to handle more possible errors.