BARB - includes television viewing figures, trends and more.
The Cinematologists - podcast and film club for discerning cinephiles
British Film Institute - watch films online (many for free), interviews with filmmakers and TV producers, statistics
Inventing Entertainment: The Early Motion Pictures and Sound Recordings of the Edison Companies
British Council Film Collection - collection of short films produced in the 1940s (during the war)
David Bordwell's website on cinema - essays, blogs. etc
Silent Era - articles about the silent era of films
BBC Archives - collections of audio and video recordings
Capturing Reality - interviews with top documentary film-makers
Radio Times 1923-2009 - listings information You can search the site for BBC programmes, people, dates and Radio Times editions.
Media History Digital Library - digitised collections of classic film periodicals and books in the public domain.
Open Culture - lots of free movies covering silent films, film noir, Hitchcock, Tarkovsky, Dziga Vertov, documentaries and more.
Prelinger Archives - 60,000 US "ephemeral" (advertising, educational, industrial, and amateur) films