Monitor Lab Usage

[mojoxp]

I've got a lab of 100 or so machines that I need to monitor usage on. They're all running Windows XP, are on a Domain, and are managed by SMS 2003. I need to find a way to monitor "active" usage on the machine, so when someone is actually sitting at the machine doing something. More specifically, i just need each instance of when this occurs.

Previously they had been using a screen saver that contacted an SQL server when it was turned off, but that no longer is a viable option. I'd like to do it with SMS so that I could combine it with the other software metering data that I collect.

I tried setting Software Metering to track the screen saver on the system, but it doesn't look like SMS is going to play that game.

Any ideas?