Viking is a free/open source program to manage GPS data. You can import and plot tracks and waypoints, show Terraserver maps under it, add coordinate lines, make new tracks and waypoints, hide different things, etc. It is written in C with the GTK+ 2.
|...hem Bonnefille||Rob Norris|
|Michael Klein||Wolfgang Goetz|
|Mathieu Albinet||Greg Troxel|