Beth and Marina: it looks like you both may be looking for the same info. Maybe you should share the resources you get.
Beth: you should look at some of the questions posted here by Marina and at the replies.
If I haven't already mentioned the orchid forum at www.ganoksin.com I'll suggest it now for information on gold and silversmithing. The forum at www.beadandbutton.com is good for beading info.
Let us know what questions you have about specific aspects of the jewelry industry and we'll do our best to help out.