actually, radio shack has the cable for 40 bucks w/ a driver disk, kinda expensive, but it does map it to a com port.
If you search on froogle, you can get one for as low as 15 bucks or so shipped. A few sites to choose from below:
http://store.yahoo.com/store4pc/usbtoser9pin5.html
http://www.more4mymoney.com/catalog/...oducts_id/4169
http://www.spacecentersystems.com/ca...oducts_id/5086
EAch one i belive works fine.