What kind of modem do you have? It's odd that it shows generic name, most routers, even if they run linux, are at least customised to show the router's actual name.
Anyway, all UPNP does is allow software (like MSN Messenger, Azureus, Trillian, eMule, etc) to open ports to your machine as needed for file transfers and other direct connections.
It also has the potential to let Viruses do the same thing as there's little control, but if you trust you're careful enough and/or have good anti-virus you can safely leave it on.
If you do want to disable it, you can either remove Networking Services > "Internet Gateway Device Discovery and Control Client" or disable UPNP on the router.