Here is where you can get adapters to make your hardware convert to USB. The Gameport to USB at Radio Shack is prolly your best bet online and at retail.

Game Commander Gameport to USB part number 26-164
http://www.radioshack.com/product.as...ct%5Fid=26-164

Interface 9 Pin Serial to USB
http://www.sewelldirect.com/USBtoSerial.asp

Here is another 9 PIN SERIAL TO USB for $13.89. This would work.
http://www.thenerds.net/productpage.asp?un=154913&s=1