FindMyPhone tries to locate your phone by GPS and network location and communicate it back to the owner. Currently supports activating by sending a secret message via SMS. The resulting location is sent via SMS

Market link:
https://play.google.com/store/apps/details?id=se.erikofsweden.findmyphone&feature=also_installed

website
http://erikofsweden.blogspot.com/p/findmyphone.html

sourceforge
http://sourceforge.net/projects/findmyphone/files/