MyConvoy is an free mobile application that communicates location data between users. You're able to enable and disable the service at will as well as toggle each person in your Convoy so that only the people you choose can view your location. Parents can be notified whenever their child leaves school or friends will be able to easily stay connected during nights out. It's currently released on both iOS and Android, however it's one week away from being in the Official Launch version. The tutorial will be drastically improved among a few other things. Thanks!