download usb overdrive x (shareware).
this will allow you to map the buttons of your usb controller to your keyboard. (ie, z, x, etc: the default mupen controller keys.)
has worked so far for my intel mac.
keep the real plugin coming!
this may be old news, but i was having trouble loading saves (ie from a *.pj file) cuz it kept freezing. i figured it out though, so thought id post the solution that worked for me. 1. load the save, emulator will pause. 2. go to emulation > pause/play, emulator will run but freeze. 3. save...