Spyderco Knives Spyderco factory website, lists all currently available models, and has a helpful glossary of knife terms.
Spyderco Forum Unlike most "company" forums, this one encourages open discussion of problems and suggestions for design improvement.
BladeForums I mainly visit the Spyderco and Knife Exchange forums here.  Some of the others get a bit rough for my taste, YMMV.
KnifeForums A kinder, gentler, forum.  Although I don't post here much I do enjoy this forum quite a bit.  Nice place.
British Blades If you think some of the knife laws in the USA suck, be thankful you don't have to put up with theirs.  However, be advised that the moderators there are spineless, and habitually delete anything remotely "controversial".
   
Spydiewiki Spydiewiki is a Spyderco collector initiative which is intended to be a central repository for information related to Spyderco history and products. It is a work in progress, but the information it does contain is accurate and quite valuable.
   
New Graham Knives Most times in life, one must choose between getting good prices, but lousy service, or getting great service but paying through the nose.  We knife nuts are supremely lucky here, as Mike Dye combines impeccable service, some of the lowest prices on the internet, and a great selection of Spyderco and other brands.   Hear that New Graham Pharmacy, the "brick and mortar" home of NGK, serves a mean country breakfast too.
   
Marcus A. Hunt Mr. Hunt is a British master engraver, and is the gentleman responsible for creating the exquisitely engraved Delica I own.  His website features several more examples of beautifully engraved Spyderco knives.
   
Santa Fe Stoneworks In addition turning stainless Spydercos into works of art by adding stone, shell, and wood marquetry onlays, Santa Fe also offers Kiwis with stone and shell scales in place of the Spyderco jigged bone ones.
   
Ted's List of Spyderco Models

 

Ted's List of Spyderco Catalogs

 

Models By Year Introduced

 Ted van der Voorde, a Spyderco enthusiast from the Netherlands, has put together an illustrated list of all Spyderco models through the years. His website is a fantastic resource for anyone the least bit serious about collecting Spyderco knives.  In addition to pictures of all models, past and present, and the ability to sort the listings by model number, by year of introduction, or by size, and the ability to see any model "life size". Recently revised and better than ever. Ted also has a page where you can download many historic Spyderco consumer catalogs in PDF format for reference.
   
Rob Fruehauf Rob is an Spyderco collector in Austria and an excellent and artistic photographer.  Great pictures, including some superb black & whites. In addition, he has recently added a VERY informative PRICE GUIDE in PDF format, showing the final or current MSRP of many Spyderco models past and present. 
   
Spyderwa Great pictures of some of the rarer models, and an excellent and very comprehensive list of "Q" variants and the number of each made. As with all Angelfire hosted sites, be prepared for all kinds of pop-up ads.
   
Dialex This young fellow from Romania does some really interesting and innovative futuristic looking knife designs.  He's the designer of the Spyderco Adventura.
   
Boxer93's Qs Chris focuses on the C-35 "Q" and his site contains photos of more of the variants, including some of the rarest, than can be found anywhere else
   
Mr. Blonde's Blog
Another collector from the Netherlands, exellent photographs and insightful reviews of a number of Spyderco models.
   
Rorschach's House O' Spyders An interesting site by another Spyderco  collector.  His Santa Fe Stoneworks Dragonfly is a true work of art.
   
CLB Design Chad Los Banos is the designer of the Spyderco Lava and several Boker knives including the SUBCOM, WHARCOM, RESCOM, and Trance folders and the SUBCOM fixed blade.