AV

Audio Visual
The New York Times has a trailer page, which includes vintage films like Bambi and American Movie.

Visual
The Library of Congress is putting its images online so that people can post comments and information to them. I use their online index for class all the time, but this might make it easier to find a category like "boston marriage." (not posted above)

Steven Hill has an index of the title images from nearly 5000 films.