GPS Tracking App iPhone / Android

We require a simple iPhone and Android app that will run in the background and periodically poll the location (eg. every 10 minutes). The location (lat, lon) is to be sent to a server. The app also needs to have a button to get the current location and send it to the server. We also need some way of updating the frequency of sending remotely (ie, "Standby", 5 minutes, 10 minutes, 30 minutes, 1 hour, etc). The app must be able to run constantly in the background and it must be able to use the GPS / Geo-Location features in a way that conserves battery (ie. only turn on GPS for the time it takes to get a position, then turn off).