Bi-directional data flow between a service and a win32 app in vista

Question

Hey there, I'm trying to create a service for windows xp & vista that gets information from the user while it is running from a win form. But because of the security issues in vista (sessions separating) I can't do it. I read something about using Global memory buy didn't really get to the end of it, because of a lack in explanation. If anyone can point me towards a certain tutorial or something, would be great. TNX guyz.