The first two links are very comprehensive and should be your first read in this category.
Suppliers list - A very comprehensive list of suppliers compiled by C. L. Wilkins
Master index of knife making material, services. and suppliers from AJH-Knves
Manufacturers list for Abrasive products, Cutting tools, CNC tooling, Hand tools, Lubricants/fluids, Measuring & Inspection tools/machines, Shop specialties, Tool & die components and Torque tools
Metalworking online resources from frugalmachinist.com
Metal links from stagesmith.com
Material Safety Data Sheets (MSDS) online
Buffing supplies from jestcoproducts.com
Custom etching by custom-etched.com
Flint knife supplies from thenaturalearth.com
Industrial supply house: McMaster Carr
Japanese Sword Polishing Items and Sword Accessories
Australia knife making supplies
Knife Machines and Tools cc / Afri-Thipa cc
Knife making materials from milesofalaska
Knife making materials from gatherwood.nl
Knife making materials from jano-knives.com
Knife making materials from ragweedforge.com
Knife making materials from crazycrow.com
Knife scales from knifescales.com
Thompson's Scandinavian Knife Supply, LLC
The knife handle material Encyclopedia (75+ pics)
Sharpening:
EdgePal sharpening system by Thomas Lofvenmark
PSA (Scary Sharp) Honing System and honing supplies by handamerican.com
Steel:
Crucible Steels for Knife Making
Junkyard steel, using recycled steel or steels of unknown pedigree
Common Railroad Steels Site having problems as of 1-22-2007
Spark testing Site having problems as of 1-22-2007
Technical guide to "Sex bolts"
http://forgegallery.elliscustomknifeworks.com/ - Ellis Custom Knifeworks
Burner components and pipe fittings
Propane regulators and assemblies
Steel for knifemaking and damascus
Books - Classes - Forums - Heat treat - Miscellaneous - Multiple tutorials - Shop - Single tutorials - Supplies - Videos