On a sidenote, you might also simply use SEGA Megadrive controllers. They plug in and work instantly - guess its not only the same connector, but the same pin layout. Some games even support the 3rd button on the pad.
Edit:
Bleh ... read first... post later... I've meant SEGA Controllers work on real Amigas. However, I've seen 9-pin SUB connector pads/joysticks brought to work via some piece of software (of course I forgot the name) on serial ports PC with UAE. That was quite a while ago, but fitting in this necro thread
