Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
Friendz - Friendz is a free GPS based app that lets you find your groups on the map & keeps you notified.
Zenly - Zenly is a GPS tracker to locate your friends in realtime.
OwnTracks - Cross-platform location sharing
Facebook Places - Let your friends help you discover restaurants, hotels, museums and more.
LockOnMe - LockOnMe is a location-sharing app, displaying targets and associated Points Of Interest on maps & fun radars.