We have made tutorial videos to this understand that the Developer Tools for UPnP Technologies can do. In the first video, we show the Network Light along with Device Spy and Device Sniffer. It's simple usage of UPnP but also probably the most common use of the tools for most people.
In this second video, we demonstrate how to use Device Builder, this is the code generator tool. We show it generating a C stack for Windows starting from an existing network device. Device Builder makes it easy build UPnP software. Also, both the tools and the generator code are licensed under Apache 2.0. This license allows the code to be used for pretty much anything including commercial use.