Gps Babel
Get gpsbabel at sourceforge.net. fast, secure and free downloads from the largest open source applications and software directory. gpsbabel reads, writes, and manipulates gps waypoints in a variety of formats. over 100 supported formats include gpx, magellan and garmin serial and usb protocols, geocaching *.loc, garmin mapsource, and magellan mapsend. for windows, linux, mac.
http://sourceforge.net/projects/gpsbabel