Artistic Blacksmith's Association of North America (ABANA)
Mountain Stream Forge seems to be making a go at blacksmithing for a living. Iron Antler Forge is a local blacksmith doing well.
If you are looking to buy tools, visit Blacksmith Supply Company, Centaur Forge, Kayne & Son: Blacksmith's Depot, or my new favorite Pieh Tools.
For some unique tongs, hammers, and other tools visit GS Blacksmith Tongs.
For all kinds of hammers visit Hammer Source. For hammer handles try the House Handle Company.
If you are looking for a maker (touch) mark, check out Columbia Marking Tools.
Looking for tool steel? Try Aldo Bruno, the New Jersey Steel Baron.
Before you buy an anvil you should read Some thoughts on anvils. Then look at Old World Anvils and Nimba Anvils.
A Blacksmithing Primer: A Course in Basic and Intermediate Blacksmithing by Randy McDaniel is a good book to get if you are just starting out.
Another good book is 101 Metal Projects for the Novice Blacksmith: A "How-to" Shop Manual for Beginners
© Ken Scharabok, Poor Boy Blacksmith Tools (An ebay store), 1645 West Blue Creek Road, Waverly TN 37185.
Artistic Blacksmith Group of Tidewater
Northeast Blacksmith's Association
Forge Fire (Indiana Blacksmithing Association)
Pittsburgh Area Artist Blacksmiths Association
Old Dominion Blacksmith Association