MapQuest Inc. in a partnership with uLocate Communications offers a new communication and people locator tool that allows individuals with GPS-enabled cell phones and mobile devices to opt into group networks to find the exact location of other people in the same group.

From the Mapquest Find Me site:

GPS-enabled maps, directions, and points of interest. Let your friends
and family know where you are.

MapQuest Find Me is a downloadable application for your GPS-enabled
mobile phone. It allows you to pinpoint your location and find out
what’s nearby. You can also share your location with trusted people via
text messages or the secure website and get maps and driving directions
to nearby places.

The Find Me service has a number of other map and search features as well.  You can read more about the service at MapQuest Find Me .