You can listen to your favorite workout music and track your run in detail at the same time with the Apple iPhone 3G and the new RunKeeper application from FitnessKeeper, Inc. It's one of a new batch of fitness and workout tracking and mapping apps made possible by the GPS capability built into the iPhone 3G.

Users like the RunKeeper because of its auto-pause feature (take a call and the run timer automatically stops) clean and simple interface and large buttons, pacing bar graph, and the ability to upload to RunKeeper.com to further analyze and store your data and display your route on Google maps.

Not a lot of extra bells and whistles (such as calorie count) in the RunKeeper, but a nice app that takes advantage of the GPS capability of the iPhone 3G. The RunKeeper app is only $9.99 in the Apple iTunes app store. How to carry your iPhone 3G on a run and still see and use the display? A sports armband is the way to go.