Brian Casel has a great post over on DesignM.ag that showcases the various opportunities that exist to run a freelance business around WordPress. Developers, designers, and copywriters all have a ton of opportunities to make money around WordPress. I suppose I would fit into the freelance journalist category even though I don’t consider myself to be a journalist. I know I’ve mentioned WP125 before to manage advertising on your site but Brian linked to one other advertising system that may suit your needs called Advertising Manager. Based on the features page, this looks to be a nifty plugin. I might review this at some point in the future.