Matt,

Check http://blogs.msdn.com/calvin_hsia/archive/2005/08/02/446742.aspx

>We have a VFP program that is running as a service on our workstations, under the system account. The service is working great, but we'd like to be able to detect when a user logs on or logs off. It seems like this should be an event that's easily bound to, but I'll-be-darned if I can find a way to do it.