More about Bill than his dad, but certainly a good read. Again, I can't recommend the Halberstam book enough--even if you have to have someone read it to you.
http://sportsillustrated.cnn.com/2005/magazine/11/22/belichick0809/index.html
http://sportsillustrated.cnn.com/2005/magazine/11/22/belichick0809/index.html