I just signed up with
Link Vault. It's a tool that allows you to exchange static text ads on your websites for the same on many others. The benefits of using this tool are two fold. First, you have direct advertising on a topically related website. The categories they use are very general, but you should be exposing your ad to people at least remotely interested in your site. Secondly, the links will help you greatly with your serch engine positions. I will post more as I get more specific results from the system.