Track your Laptop

There is some free and open source software that can track your laptop with that may help you get it back in the event that it's stolen - provided, of course, that you had the software installed before it was stolen and the thief is stupid enough to connect to the Internet with it. It's very new software and is still being heavily developed, but a working version of it is available for Windows and Macs.

Adeona is named after the Roman goddess of safe returns. This system is the result of recent academic research started at the University of Washington, with participants now also at the University of California San Diego and the University of California Davis. The foundations of the Adeona design — and an analysis of its security and privacy properties — are published in a research paper at the 2008 USENIX Security Symposium.

-from the Adeona home page.

Did I mention it's free?