For those of you with i-phones there is a free app called runkeeper. Have a look at it on runkeeper.com. My friend rides his bike into work with his iphone in his rucksack and he has been showing me how the app works and it does look useful.
RunKeeper is an iPhone application that enables you to use the built-in GPS in your iPhone 3G to track all of your outdoor fitness activities, including duration, distance, pace, speed, elevation, calories burned, and path traveled on a map. You can store all of your historical activities on the RunKeeper website and share them with your friends.
You can also add photos to planned training routes.