Where can I watch Late Show with David Letterman in United States?

Late Show with David Letterman is an American late-night talk show hosted by David Letterman on CBS. The show debuted on August 30, 1993, and is produced by Letterman's production company, Worldwide Pants Incorporated and CBS Television Studios. The show's music director and band-leader of the house band, the CBS Orchestra, is Paul Shaffer. The head writer is Matt Roberts and the announcer is Alan Kalter. Of the major U.S. late-night programs, Late Show ranks second in cumulative average viewers over time and third in number of episodes over time. The show leads other late night shows in ad revenue with $271 million in 2009. In most U.S. markets the show airs at 11:35 p.m. Eastern/Pacific time, but is recorded Monday through Wednesday at 4:30 p.m., and Thursdays at 3:30 p.m and 6:00 p.m. The second Thursday episode usually airs on Friday of that week. In 2002, Late Show with David Letterman was ranked No. 7 on TV Guide's 50 Greatest TV Shows of All Time. CBS has a contract with Worldwide Pants to continue the show through 2014; by then, Letterman will surpass Johnny Carson as the longest tenured late-night talk show host.