A top CBS News producer was busted Thursday for trying to shake down David Letterman - threatening to expose the late-night funnyman's affairs with several female staffers in a movie and book. The "Late Show" host revealed the stunning plot on last night's show in an extraordinary confession to viewers - and admitted he had indeed slept with several women who work at the show. "I'm glad you folks are here tonight, and I'm glad you folks are in such a pleasant mood, because I have a story I'd like to tell you and the home viewers as well," he...