PigskinHeaven.com
   NFL, College, and fantasy football forums.
   http://www.pigskinheaven.com/

Quarterback Passer Rating Calculator
   Rates quarterbacks by attempts, completions, passing yards, touchdowns, and interceptions. NFL, NCAA, and Arena Football League calculations available.
   http://www.primecomputing.com/

SearchQB.com
   Customized search engine focused on football.
   http://www.searchqb.com

Wikipedia: American football
   Encyclopedia article covering the history of the sport, its popularity, rules, basic strategy, and physicality.
   http://en.wikipedia.org/wiki/American_football