The application is licensed as Free Software under the GPLv3. It is available via F-Droid for easy installation and updating.

F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device. It is particularly helpful on Android devices to replace or augment the Google Play store, and when de-googlifying such mobile devices.

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/