All in One Adsense and YPN is a Free and Open Source WordPress plugin by linewbie which is able to automatically insert google adsense ads or yahoo publisher network (YPN) ads in to your posts on the fly.
It doesn’t matter if you have 1 post or 100,000 posts, it will insert your ad code into all of them automatically. You can control all aspects of your ad’s display and position. Just specify ad color and position in the plugin options, your ad code is automatically generated and inserted. Advanced users can add html and css code before and after the ad to have total control of the ad display.
Automatically insert Google Adsense or YPN ads in to your blog posts.
No manual work required, ad code is dynamically inserted into your existing and new posts.
You could optionally specify not to show ads in a post by using tag
You could optionally specify where to start the ads in a post by using tag
You could optionally specify where to stop the ads in a post by using tag
Decrease ad blindness by giving you the option to randomly place your ad within your posts.
You could optionally define absolute ad position instead of random position.
You could optionally define random ad network to maximize earnings from both networks.
Allow you to pick how many total ads to show on one page.
Allow you to pick how many ads to show in one post.
Compatible with the new WP MU mode.
Download and info: http://wordpress.org/extend/plugins/all-in-one-adsense-and-ypn/