Google's My Tracks takes the same idea and wraps it around the idea of improving fitness and the community of those who like to share their fitness activities.
My Tracks is only for the Android-based HTC G1 at the moment.
According to Dylan Casey, product manager and former professional cyclist, "My Tracks records tracks of outdoor activities using the phone's built-in GPS. It shows these tracks on a map and presents live statistics, including an elevation profile. And here's the best part: it lets you easily share your activities with friends and the world using Google Maps, as well as archive your training history with Google Docs."
Not only will you have a way to record your circuit, but you'll be able to share it with friends who may enjoy that particular road, path, or route.
It offers a bunch of tools and capabilities. With My Tracks, you can record and visualize GPS tracks while running, hiking, biking, skiing -- or any other outdoor activity; get live statistics, such as total/moving time, (average) speed, distance, and elevation profile; send performance statistics to Google Docs to build a training history; and mark places and describe activities for others to discover via Google Maps.
Since I don't have a G1, and it is a little windy today to take my bike out, I haven't tested this software, but I like the idea a lot. During the warmer months of the year, I enjoy a good bike ride. Being able to track, map, and share my route with others would be a lot of fun.
My Tracks is a free download from the Android Market on the G1.
Here's a video introducing how My Tracks works: