I Spy: Show summary, episode guide, photo gallery, cast info, and quotes.
I Spy: A Tribute to the Coolest Spies in Television History: Episode guide, cast profiles, image gallery, series concordance, and message board. Also offers information about related films, books, and comics.
IMDb: I Spy: Cast and production information.
TV.com: I Spy: Show summary, episode guide, cast bios, reviews, and a forum.
Yahoo! Groups: I Spy: Show, cast, and character discussion. [Yahoo! registration required.]