I should begin this with a disclaimer that I did not try this resource yet, and only just recently discovered it. That all being said, I am quite happy to find something other than proprietary things out there.
It seems, for now, Pombo only runs on Linux clients. Even that, though, helps many of us with Linux machines. More schools also purchased many Linux netbooks, so this will help them as well.
Seems like a simple enough application. It consists of a python and php file, and runs in the background constantly. Once you discover your laptop stolen, you login to the webserver you create, get the information from the last connection of the laptop (IP, date/time, nearby routers, and even a photo if your laptop contains a webcam), and you can turn this information over to the authorities. Pretty neat, while simple tool. And definitely a helpful tool!
Find Pombo here: http://sebsauvage.net/pombo/