Bebop World
Contains character profiles, an image gallery containing art book scans and official posters, media downloads, episode scripts, song lyrics and an interactive fan forum.
Cowboy Bebop on Wikipedia
The online encyclopedia article on the show contains a thorough, but concise history of the show and its featured characters. This is a good starting point for newer fans.
Emily's Cowboy Bebop Page
Story, characters, episode guide, music listing, merchandise and WinAmp skins.
Knockin' On Heaven's Door
Archive of the official site for the movie. Features Big Shot, Bebop: UT, and summaries. [Japanese and English]
Swordfish 2
This site contains news, an image gallery, fan art, links, and shopping.
The Jazz Messengers
News, summaries, edits, references, gallery, merchandise, and downloads.
The Lone Gunman's Cowboy Bebop Visual Guide
Guns, aircraft, vehicles, and links.