Just in case anyone tries to steal my brilliant idea and patent it for themselves, I'm going to write it here!
The topic of accessing and controlling Windows Services from Unix comes up from time to time, with no real good answer. The only thing I found was something from Microsoft and it wasn't free (I think).
As I was preparing my slides for OSCON, working out the Services stuff, it hit me. I would simply setup an XML-RPC server as a Service, and define whatever functionality I needed within the XML-RPC server which I could then call from a Unix box. This would probably be methods that return info about the system via WMI or user and group info via Win32::NetAdmin.
/me runs to the patent office