I'm not sure about your OS, but if you are on XP and your router supports UPnP (not PnP, that's different), wouldn't that take care as long as...
1 - You had UPnP enabled on your router
2 - The "SSDP" and "Universal Plug and Play" services are set to automatic AND running in XP
3 - Your torrent software supports UPnP (BitComet does I know)