I set up a no-frills Google Spreadsheets file to track my cycling rides this year. The spreadsheets allow you to record the route, distance, time, average speed, and weather conditions of your training sessions.
I designed the document for cycling, but you can also use it for running, walking, cross-country skiing, or some other distance exercise.
Feel free to download and use the sheets for personal, non-commercial use.
Additionally, I have also been recording my rides online at BikeWire.