Need automated link plugin for Wordpress

Basically what I'm looking for is a plugin for Wordpress that will allow me to contextually match up my sidebar links to the active page content.

For example, if I have an article about "pigs in space" on one of my link farm blogs then in the sidebar I want to only show links in my inventory that are about pigs or space.

My theory here is that more link juice will be passed because the link would be relevant to the content.

Does something like that exist? I guess what I'm really asking for here is my own copy of AdWords. lol

I did find a plugin for OpenX that supposedly allows contextual targeting, but it's $300 with no trial that I could find...and not a lot of info on how it actually works.

Anyone have any feedback on this?

If you don't find anything I can make a Wordpress plugin for you for 200$ in a matter of days and you get all the copyright. PM me if interested.