There must be additional media companies with public-facing APIs – these were just the obvious ones that showed up in a Google search. Interested though in who has developed internal APIs that are used for product development, not public use?

 
New York Times
http://developer.nytimes.com/
NPR
http://www.npr.org/api/index
ESPN
http://developer.espn.com/docs
The Guardian
http://www.guardian.co.uk/open-platform
BBC
http://www.bbc.co.uk/programmes/developers
USA Today
http://developer.usatoday.com/
Associated Press (subscriber only)
http://developer.ap.org/capi
Huffington Post Polls
http://elections.huffingtonpost.com/pollster/api