Where's My Droid was the first 'find your phone' app on the Android Market. Designed to track down missing/stolen Android devices, Where's My Droid can get the GPS coordinates with a link to Google maps to help locate devices. You can track your phone using the online commander or using a text message to send an attention word to activate tracking.
Where's My Droid also informs you if the SIM card on your Android device is replaced, by sending the SIM card number and cell number details to a designated number. It uses whitelists/blacklists to control the numbers that can activate the app's features. Once activated, the app works silently in the background to activate the GPS and send back the relevant information to the designated number or to your online commander account at WheresMyDroid.com. The pro version allows for remote lock, remote wipe and activation from landlines. Where's My Droid does not require root.