From Wise Orbit Labs:
UPnP Port Works (UPnPPW) is an all purpose platform independent application that aids router management. Its framework, pioneered under C is fully compliant with Microsoft's UPnP technology. Furthermore, this independent solution consumes very little system resources, and requires no administrative rights. The easy to use console application provides the user with detailed information pertaining to the issued commands, and at the same time delivers an unparalleled troubleshooting interface. UPnPPW also offers a flexible set of commands that range from modifying or viewing port forwarding entries to retrieving pertinent router information.