How can a freelance programmer market himself to potential clients? Does his resume do most of the marketing for him?
Your resume can be of help to catch someone's interest, but will not do the most for you. In terms of marketing, likely the best thing you can do to start is a) have a professional looking website, and b) have a portfolio/demos (even if you have to do a few quick free jobs to build that up).
Marketing and sales are two entirely different things though. Marketing is about getting yourself noticed and piquing interest. Sales is about convincing people that you're the one that they want to work with, and the best way to do that, in my opinion, is through conversation.