I use the "Miles Tracker" program written by a good friend and rider, Jason Jonas.
Its free and easy to use. It is broken down into catagories, you can list as many bikes as needed and you can print reports from it for cost or annual mileage or whatever. Great program, the main page on the site shows each riders lifetime miles.
I am currently at 488,000 miles.
http://miles.jasonjonas.com/