I found an absolutely brilliant google map hack the other day, called GMap Pedomoeter. I allows you to track a route using Google Maps and tells you the distance etc as you go along. Its great for measuring out running routes, so I decided to measure out the route for the Great North Run, which I shall be running in a few months time.
Update: Damn, not doing the great north run now – Caroline’s had a muscle thing go in her leg and my knee is playing up. Actually its lightened the load a bit and reduced the stress :)