google has release a tool called google latitude which ties into google maps your location.
currently there is not an iPhone app (though one is in the works and is expected soon) – there is one for the Blackberry (which I played with last night). It worked well and I could see how this would be really cool to share with a spouse or child.
For instance, my wife calls to see if I made it on the train and will be home on time. With Latitude, I would share my location with my wife (everything is off by default for those concerned about security) and she could see me passing the South Orange station and arriving to Maplewood on time. Cool!
Say I want to catch up with some friend, again, Latitude would allow me to see that a friend is close by at a restaurant and we could meet up.
As they say, “location, location, location…”