I have written an article about teaching with GPS, which can be found at Juicy Geography. The page includes links to some Google Maps I prepared that show how GPS Visualizer can be used to plot fieldwork data.
GPS Visualizer seems to grow new features each week and is a brilliant application for displaying yourGPS data.. The other essential utility featured is Easy GPS. I hadn’t realized until recently that it now manages GPS tracks as well as routes and waypoints. Both these programs are free.