Sound effects and music etc

http://www.filmsound.org/articles/horrorsound/horrorsound.htm

http://www.psychomovie.com/production/prodhitchcock.html

http://www.scriptsecrets.net/articles/psycho60.htm

http://www.wowessays.com/dbase/ac3/ena146.shtml

http://web.tiscalinet.it/andrebalza/stevens.html

Quite a bit of cool stuff on this site:
http://faculty.cua.edu/johnsong/hitchcock/

A study guide which provides some general coverage of ideas - some worthy of inclusion for you
http://www.filmeducation.org/filmlib/Psycho.pdf