I recently joined an affiliate program for Make Your Site Sell (an e-book that does exactly what it says in the title). When I joined up I got a free e-book for affiliates which was crammed with great information about selling anything on the Web. I would really recommend this to everyone; even if you decide not to participate any further after you've downloaded the free book.
Having said that, it's the best affiliate program I've found so far. http://www.sitesell.com/
[This message has been edited by jonese (edited March 19, 2000).]