Josep just sent me a link to a new piece of free software for BlackBerry called PLT7. The idea of PLT7 is to keep track of when a BlackBerry enters or leaves a specified zone based on your specification. You select an area in Google Maps online and the software will automatically notify a cellphone or email address when you enter or leave that zone. You can also let people track your travel by giving them a pin number to access your route. You can even track multiple devices at the same time. Pretty cool stuff! I guess maybe you can let big brother watch you.
I can see a handful of uses for this including tracking employees and letting family know when your close to home. The cool part is that the application is free but according to the website it has only been confirmed to work on the BlackBerry 8310 with GPS. They claim to also have support for Bluetooth GPS and other GPS devices but I cannot confirm or deny.