There are many tools available to create, edit, convert and analyze GPS tracks.
Viking is great for working with, analyzing and editing tracks, looking at them on different map sets (topo, plain, etc.) and quite helpful when planning an outing.
GPSbabelGPSbabel is the universal GPS format translator. It can handle many formats from all kinds of devices, and is a Swiss-Army-Knife for handling track files.
GPSVisualizer can help you check your rides, get elevation profiles, and also convert Google Maps URLs and KML files to GPX tracks. If you have a route in Google Maps, you can copy and paste the URL into the URL field and get a GPX track for your phone or GPS.