Google "pulled the curtain off" Site Targeting, an AdWords feature that lets you target certain web sites where you want your ads to appear. You can also use animated image ads, in addition to the standard text and images.
These ads will compete in the same auction with CPC (cost-per-click) ads and allow you to bid for placement on a CPM (cost-per-thousand-impressions) basis.
Read more about Google's new Site Targeting features
here...
Search Engine Optimization Blog Article...