You may recall a few months ago, I mentioned an SEO Firefox extension created by SEOpen. I use this extension a lot, and still think it is great. Well, now SEOpen has another tool on its site that I started using last night, and it is very nice as well. Basically, you run a search (using Google API) to find sites interested in exchanging links based on the keywords you enter. I discovered lots of good sites that I had not found through my own search trawls, so the tool has already helped me. Check it out at http://seopen.com/seopen-tools/link-development-tool.php.