For windows, linux and osx.
I have been using this for a while and figured that some other people might find it useful so I am posting here. Cheaper than paying for some other software packages.
Prey is a lightweight application that will help you track and find your laptop if it ever gets stolen. It works in all operating systems and not only is it Open Source but also completely free.
Prey checks if theres an active internet connection to send the information. If not, it will attempt to connect to the nearest open wifi access point available. This gives you a better chance to locate the device.
You can alert the user hes being chased at by sending messages whichll appear on screen. You can also trigger alarms to make the message clear not only to him but also to whomever is nearby. Be careful with this one!
How it works:
Prey wakes up at a specified interval and checks a URL to see if it should gather the traces and send the report. If the URL doesnt exist, Prey will simply go to sleep again. Basically, thats it. This can be controlled free from the preyproject website or you can host it wherever you like.
If you laptop is stolen, log in to the control panel, flag the laptop is stolen, then wait for an email with the link to a screen cap, ip details and webcam picture.