Zenly - Zenly is a GPS tracker to locate your friends in realtime.
Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
YouMap - The Human Atlas™
Babble - A more personalized social network
LockOnMe - LockOnMe is a location-sharing app, displaying targets and associated Points Of Interest on maps & fun radars.
sup - The first creep-free way to see nearby friends