Using your mobile to help stay in shape is a good idea, but there's really no need to buy a separate phone to do so (unless you want additional hardware functionality, like being able to hook it up to your running shoes).

There are quite a few Java applications out there to do so that work on most new mobile phones, like GymTracker to track workouts and KCal to monitor calorie consumption.

Wait... so is someone other than Microsoft getting credit for Clippy? And since when do they have more than one invention?