Phonelocator - locate your phone
Phonelocator for Android Alpha
Phonelocator for Android Alpha is available for free on HockeyApp here
Open source
Phonelocator for Android is open source, the souce code is available on github here. Please fork the project and add features!
Alpha quality
Phonelocator for Android is alpha quality. This means that it is unstable. It's concebable that it could eroniously transmit large quantities of data, cause crashes or data loss.
You have been warned!
Phonelocator Periodic for Symbian OS
You can see a list of compatible phones here.
Version 1.0.34 (available 14th January 2011)
Version 0.9.27 (released 18th January 2010)
Available free of charge