I've just subscribed to www.freelancesuccess.com which promotes itself as the ultimate resource for established, professional non-fiction writers. I've avoided these sites in the past as they never live up to expectations, however Freelance Success really is an excellent resource. The newsletter and the forums make the membership fee worth every penny. In my first few days I came across a ghostwriting opportunity that was perfect for me; answers to some questions I had regarding pitching Reader's Digest and a whole lot more. I also made friends with several writers who work out of their homes and face the same issues as I do everyday.