CNN Transcript Collection (2000-2012)
From the webpage:
For over a decade, CNN (Cable News Network) has been providing transcripts of shows, events and newscasts from its broadcasts. The archive has been maintained and the text transcripts have been dependably available at transcripts.cnn.com. This is a just-in-case grab of the years of transcripts for later study and historical research.
Suggested transcript sources for other broadcast media?