FitnessKeeper Inc.

iPhone App: Using the iPhone's GPS capabilities, you can track your fitness activities, including distance, time, speed, pace, calories burned, elevation, and path traveled on a map
Store all of your activities on your personal web dashboard at www.runkeeper.com, where you can keep track of all of your historical activities and monitor your progress.
Make your activities public, and you can broadcast your success to the world. With auto-sharing features, your results can be sent to Twitter and Facebook as soon as you finish your activity!