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.