This site is in it's beta, thus imperfect but as I don't have a mileage calculator or a nike+, this is the next best thing.  I put in a couple of the runs that I did these last weeks to see just how far I went each time.

This site roughly calculates your mileage and, using a google-earth-type mapping system, shows you a graph of the hills and terrain.  The site also allows you to place water spots, points of interest, views, bathrooms, etc.

The idea is great but it needs some work.  I wish that they would let you delete points (they only give you 100 and Rome has some cuuurveeeyy roads) so I don't know how accurate it is.  One is very limited while making the map and if you mess up, you have to start again from the beginning. 

Also, graphically, I find the site to be below par, with cheap-looking banner ads at the center of attention. 

I'm giving it a 6.5 out of 10 for effort (for now), and for answering that undying question in my head "How far am I going today??"

I'm interested to see where this site will go in the future.