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Groundspeak Inc.: Geocaching the Official Global Gps Cache Hunt Site
Geocaching is a unique online treasure hunt game. Players 'hide' a cache anywhere on the globe and other players must follow the clues to locate the cache. Great for getting practice using GPS. There is plenty of guidance to playing, as...
Google
Google Earth Blog
The author has extensive experience using GPS and has worked with NASA. In his blog he posts information about the latest uses and applications of Google Earth.