Or, if the option is there, make a killer product and attach a good affiliate program to it. I've long been amazed Pragmatic doesn't have one. I have the perfect audiences for much of their stuff but there's not much motivation to rave about it and, even when I do, I might as well link to Amazon (meaning they make less money).
I linked up Trevor's book in JavaScript Weekl recently simply because it was such a big deal but I couldn't make a bean from it (not always the point, but if I have two choices..)
BuySellAds.com helps with finding sites to advertise on directly, but most of the sites listed there are clustered around a small number of topics.