My sincere advice is: Take a class or study a book before you start. Believe me (and I know this by very painful experience!) it's WAAAAY too expensive a material for you to be wasting it by learning as you go.
Here are a few more links:
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PMC Guild home page. Nice galleries!
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'The Alchemy of Precious Metal Clay With PMC, jewelry makers turn clay into silver or gold", Lapidary Journal article here
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'An Introduction to the Material, Tools and Techniques of Working with Precious Metal Clay' from the Society of American Silversmiths
-- And here's Timmy McCreight's book
Working With Precious Metal Clay, from Brynmorgan Press
Jan