Hi,
The cheapest way to do this is to buy a so called 4-player adapter or build one yourself. This thing originally plugs into your amiga parallel port but can also be used with a parallel port on your PC with a special driver (PPJoy) and ads 2 amiga joystick ports to your pc. You then can use the joysticks in every Windows program or emulator!
You can buy the adapter very cheap at for example
www.vesalia.de for 6 euro, look for '4-Player Parallel Adapter for Amiga'.
The driver can be found at
http://www.geocities.com/deonvdw/Docs/PPJoyMain.htm The Competition Pro is a good alternative as someone mentioned before, but I like my old Arcade Suzo very much and then this is the easiest way to go.
Happy playtime,
Roland
