If you don't have a serial or game port available on your pc
You can get a:
game port to usb adaptor
serial port to usb adaptor.
NOTE: Each adaptor requires its own USB port

For a game port to usb adaptor we recommend:
ROCKFIRE USB JOYSTICK CONVERTER - model RM-203
NOTE: Please set the MODE to 3

For a serial port to usb adaptor we recommend:
PERACOM USB SERIAL CONVERTER - model US1000A
GoHubs inc. USB SERIAL CONVERTER GO-COM232 - model US1000B