Found this piece of free software, might be useful for the health nuts ? ..
TrailRunner 1.8 is a free Leopard route planning application for sports like running, biking, hiking, inline-skating, skiing and more. If you ever asked yourself how long your workout routes are and what route you should choose, then TrailRunner can help you. It can calculate a route of the desired distance and export directions to your iPod or iPhone. It gives you a realtime, detailed orientation while you exercise.
Note: Release 1.8 is for Leopard only.