TrackMe is a GPS tracker. It's the conversion of the popular tool originally written for Windows Mobile 5 and 6. It uses the location services on your phone to retrieve your current position. That information is later used for displaying tracks (realtime or pre-recorded) with Google Earth, Google Maps or other tools. You can also export your data to other formats.
Note: This version of Windows Phone 7 still doesn't have all the features than the original one, but if people keep interested I will continue adding them periodically!