gothamist has a post on the Freelancers Union … with a chart showing income … complete report here (pdf) …
freelance writers have been around for a long time … The Authors Guild was established in 1912 … and the National Writers Union was established in 1981 …

• Elance
• See Andy Budd’s “Top Tips For Freelancers” … and the comments …
• “Free Agent Nation: The Future of Working for Yourself,” by Daniel Pink (Warner, 2002)
• Review by Colin Brayton of “The Rise of the Creative Class“