|It's an external drive? Any adapter cable will likely cost more than just buying a USB zip drive on ebay.|
Or you can add a PCI SCSI card to your PC and connect it that way.
The external connection on the zip drive should be Future Domain SCSI connection. It looks like a PC parallel port but isn't. Also, a parallel port cable won't work but I guess you have the SCSI cable. As far as I know, that cable is the same for both mac and PC.
So if you look for a SCSI card it would need to have the Future Domain type external connection.
You're not really green until you're soylent green.