David Letterman on CBS Through 2010

David Letterman has signed a contract extension that will keep him humoring audiences on CBS late-night through 2010. The host of Late Show with David Letterman celebrated 13 years with the network in August, and will have 25 years of late-night under his belt come February 2007.

Rival network, NBC, has already revealed their plan to pass the torch from Jay Leno to Conan O'Brien in the competing time slot by 2009. Conan currently hosts his own show, Late Night with Conan O'Brien, directly after Leno's Tonight Show.

With contracts ending for other late-night personalities, Jimmy Kimmel (ABC) and Jon Stewart (Comedy Central), there could be a major shake-up over the next few years. FOX has expressed interest in trying to get back into the weeknight competition, to further add to viewers' choices.