The best way to stop anything from being stolen is prevention. Apart from the obvious physical steps you can take to prevent your Blackberry being stolen by thieves, there is also a free app that BlackBerry has released to help you find your protect your device.
The app is called BlackBerry Protect and it is free to download from BlackBerry's App World. This app lets you use your phone's GPS to locate your lost phone via a map on the internet, display a message on your phone's screen e.g. 'reward if returned to…', it also lets you back-up, wipe and lock your phone remotely. Here's a quick guide how to install and use BlackBerry Protect.
Open App World on your BlackBerry, click on the magnifying glass symbol and type BlackBerry Protect into the search box.
Download, install and run the BlackBerry Protect app. BlackBerry Protect will then ask you to enter or set up your BlackBerry ID. Once you have done this, you can set your BlackBerry to automatically back itself up whenever you have a Wi-Fi connection. Automatic back-ups will not effect your use of the phone. We recommend you select this option.
Once you have entered your BlackBerry ID into BlackBerry Protect you can go to http://us.blackberry.com/apps-software/protect/ and enter your Log in details. From this site you can; View Current Location of your device, set your phone to Loud Ring - to help you find it if you've lost it nearby, Display a Message on your home screen, Lock Device, Wipe Device and Back-up and Restore you Device.