Skyhook uses WiFi to track your stolen laptop

Only works if whoever stole your laptop or WiFi-enabled handheld logs on to one of the WiFi hotspots in their database, but Skyhook Wireless is offering a new positioning system that uses WiFi to help you get your hands on your stolen electronics. What they've done is compiled data about 1.5 million public and private wireless access points and then tagged them by geographic location so that when the thief tries to check his or her email they can get a pretty good idea of where they are (whether you feel like delivering some rough justice on the perp is entirely your call).