I don't use this protocol currently, but some of devices I know do support UPnP. Also today (13-Aug-2007) I learn that UPnP protocol is approved as ISO standard. There is some other competing standards, but looks like UPnP becoming popular.
The TS-109Pro supports UPnP by default.
Currently I have decide not to enable it because some security conserns rasied by GNUCITIZEN. For more information read: Hacking with UPnP (Universal Plug and Play)