Big Red Here
One of the few sites dedicated to Late Show announcer Alan Kalter.
http://www.stormpages.com/kentymac/bigred/

Bill's David Letterman Page
Bill Lehecka's Late Show fan site, with trip reports, archives of his column Late Show Impressions, and other Letterman-related content.
http://www.oldmatador.com/letterman/

Bob Borden
Official site for the performer. Includes diary, photos, video clips, articles, and FAQ.
http://www.bobborden.com/

Helen's Dave-O-Rama
Fan's commentary on the show, accounts of trips, pictures, and progress of a "David Letterman tulip poplar" tree's growth.
http://homepages.together.net/~hpr/daveorama/

Kevin Nagle's "Late Show with David Letterman" Web Site
Pictures, links, sounds and music.
http://www.utvs.com/knagl/letterma.htm

Rest of David Letterman
Includes screenshots of Letterman guests from the late 1990s.
http://letterman.iscool.com/

Stupid Fan Tricks
News, weekly guest list, contests, biography, and quotes.
http://stupidfantricks.tripod.com

Traci's Hoosierland Salutes David Letterman
Includes transcripts, reports of trips to the show, account of meeting the host's mom, Dorothy, and pictures.
http://www.cowgirls-dave.com/