Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
TICE - TICE App – Find, locate and meet friends, family and others easily and securely. Share your location with others, set meeting points and see, when and how everyone arrives. Available for iPhone now!
Pathshare - Pathshare is a beautiful app that helps you share your path in realtime.
Flare - Friend Locator - Track your friends and family location in real time.
Foursquare - Foursquare is all about helping you find new ways to explore your city.