Ski/Snowboard Construction Related Links

Durasurf (base, topsheet, sidewall materials)
Poly Hi Solidur (plastics)
Nazdar (screen printing inks)
Sericol (screen printing inks)
Revchem Plastics (composites and epoxy)
Advanced Composites Group
Vectorply (composites)
Kevlar
QCM Industrial (epoxy)
West System Epoxy
Titanal-sports (metal for skis and other products)
CAMAX Tool Company (inserts)
Graf Snowboards (resource for building snowboards)
Michael's Enterprises (heat blanket)
SnowBoardMaterials.com (materials for building snowboards, and of course, skis)
Boardcrafer.com (materials and forum for building snowboards)
Blank Slate Skis (materials for building snowboards and skis)
The Ski Lab (custom skis and ski building materials and supplies)
Coda Boards (Custom boards, skis, and graphics printing service)

European Suppliers
IMS Plastics (base, topsheet material - France and Germany)
Waelzholz-Huber (edges - Austria)
Metalldeutsch (edges - Austria)
Swiss-Composite (composites, resins - Switzerland)
R & G  (composites - Germany)
Mates (composites, Italy)
Global Composites (database of composites companies)
boardbuildingsupply (ski/snowboard building supplies)

Ski and Snowboard Manufacturers

Black Diamond
Rossignol
Karhu
K2
Volkl
Salomon
Dynastar
Igneous
Elan
Line
4FRNT
Armada
DB
Faction (Switzerland)
Lacroix (France)
Liberty Skis (US)
Birdos (Switzerland)
Pure (Germany)
Blossom (Italy)
Aluflexs (France)
Boheme (France)
Pogo (Germany)
Skis Bois Tardy (France)
Masurao (Switzerland)
Slouch (a Reno-based snowboard company that also manufactures cores, sidewalls, and molds)

Miscellaneous

Spirakut (tuning tools)
Tognar (tuning tools)
Turns-all-year.com (World's best backcountry ski/snowboard site.)
Telemarktips.com (This is where most of them hang out.)

*Thanks to Davide Uglietti for providing most of the European based links.