Root Tracker is source code for a super-simple Android 2.2+ device tracking system that responds to SMS messages with embedded control passwords. Root Tracker is designed to be installed on a rooted device in /system/app, so it can survive a hard reset. Root Tracker has no user interface, all the better for hiding it from a thief. The code must be customized for the particular user and device, as passwords and other configuration items are hard coded, and each user should change the package name and other details to make it sound like a system package, in order to even better hide the package from a thief. Plus, I expect that different users will have different requirements.