The Godfather (1972) - IMDb
http://www.imdb.com/title/tt0068646/
The Internet Movie Database page about The Godfather, including a comprehensive list of cast, crew, technical specifications, and interesting trivia.
The Godfather - Rotten Tomatoes
http://www.rottentomatoes.com/m/godfather/
An aggregation of all reviews of The Godfather, with a 100% positive rating.
The Godfather - Official Movie Site
Information about the entire Godfather trilogy as well as updates about new restorations.
The Godfather Screenplay
http://www.awesomefilm.com/script/THEGODFATHER.txt
The entire text of The Godfather screenplay by Francis Ford Coppola and Mario Puzo