Salt Dough World
Recipes, tips, a photo gallery of finished projects, and step by step instructions.
http://www.multihobbies.com/saltdough/

PaperClay Products
Technical information, how it works, and product descriptions.
http://www.paperclay.co.uk/

Pioneer Thinking: How To Make Modeling Clay
Variety of recipes using household items.
http://www.pioneerthinking.com/modelingclay.html

PolymerCAFE Magazine
Quarterly print magazine exploring the art and craft of polymer clay. Subscription information and a submission area.
http://www.polymercafe.com/

Chessarts
Handcrafted chessmen, each one an individual. Production information, history, and a gallery.
http://chessarts.de/