The site gets quite a few hits from people who are looking for the Orson Welles movie and not the best Michael Caine information available, so hopefully this short section will help you out.
- Citizen Kane IMDb profile - Full information from the Internet Movie Database
- Wikipedia: Citizen Kane - background, review and information on the influence the film has had on successive generations of film-makers
- The Greatest Movies: Citizen Kane - exhaustive look at the movie and its resonances [contains plot spoilers]
- Full Citizen Kane script - read the entire script online
You can find lots more reviews over at the Movie Review Query Engine.