A Dutch company has introduced a small downloadable program for mobile phones, called SimWatcher, which sends out an SMS message when someone steals a mobile phone and replaces the SIM card.

The software reveals the number of the person who stole the phone and will also display a message on the stolen phone, saying tha it belongs to someone else.

The software - a demo is available here (instructions in Dutch) - costs €10 and is available for almost every type of GSM phone. The software can be installed by sending a message with an attachment or by WAP.
SOURCE: The Register