Possible Duplicate:
Can a Mac be used by multiple users at same time?
Is it possible to interact with a disconnected user session in Snow leopard (using e.g. VNC)?
I am referring to functionality similar to the administrative Remote Desktop in Windows (at least Windows 2003, I guess Vista has it too), that lets another user log into his disconnected session without interrupting the "console user".
My guess would be that the basic support for this would be there with Fast user switching, but I need some kind of server software (third party, maybe) to make it work like this. At least I couldn't find anything built-in. I tried to find a VNC server with support for this, but none of the ones a Google search provided me with had support for it...