There’s an application out there for blackberry devices called WhereAreYou.
WhereAreYou listens for text messages with a certain keyword in them from a certain list of numbers that you can configure and then in response it automatically replies with a text message containing the latitude/longitude coordinates, plus a link to Google Maps to visually locate the device on a map.
It only costs $5, comes with life time updates and and only requires 16KB of space on your device.
In the case where the device does not have a satellite fix it’ll keep trying in the background.
We wonder if its possible to have this application run completely hidden…