Prey is program that you install on your phone or laptop, and should the device ever get lost or stolen, you can remote trigger a number of actions to protect your data, and hopefully, recover your property. From the Prey Project:
Some of those actions include taking pictures of the thief, sending location information, taking screenshots and password protecting the computer. A lot like Apple's Find my Phone feature except it works on Android based devices, and laptops running Windows, Mac OS, and Ubuntu.
Basically you install a tiny agent in your PC or phone, which silently waits for a remote signal to wake up and work its magic.
This signal is sent either from the Internet or through an SMS message, and allows you to gather information regarding the device's location, hardware and network status, and optionally trigger specific actions on it
Free and open source.