Classical Music in Movies & Television
Compiled by the search engine About.com, this page provides annotated links to several online resources indexing the music used in movies and television.
Classics from the Silver Screen: Classical Music in Movies
While this site has structural issues, it is still a valuable resource for preliminary research in identifying which pieces of music were used in given movies.
Televised Opera and Musical Comedy Database
This database provides historical descriptions of thousands of televised operas and musical comedies. The information provided includes title, composer, performers, transmission dates, directors, producers, etc.