I recently came across a great contest about Adsense integration.
The challenge was to take this page, redesign it completely, leave the content in there. Everything else is negotiable. Adsense should be placed in the page twice.
Goal: To completely integrate Adsense and make it appear to be part of the site. That is to say, Adsense should appear to be internal navigation, not advertising.
The results of this contest can teach you more about Adsense integration than many $99 e-books. Take a look: