I was recently introduced to the too-cool website, reel-librarians.com, dedicated to librarians depicted in film. There is a blog exploring portrayals and representations of the vocation on celluloid. There is also an exhaustive list of librarian appearances in movies, ranging from major to bit players.
Included is what has to be the greatest librarian film ever made, Party Girl(1995). Parker Posey (in the role that made her the indie-darling she is today) plays Mary, a New York free-spirit, who finds her salvation in the Dewey Decimal system. This quirky gem is a true love letter to the library.
The Shawshank Redemption (1994) comes in a close second, as far as librarian films are concerned. In it, Andy Dufresne (Tim Robbins) uses his position as inmate librarian at Shawshank Prison for the greater good, as he executes a delicious (and much deserved) revenge scheme.
Other worthy films included in this awesome site: