For example, Dicks Sporting Goods uses Google Checkout and a search for a keyword they are bidding on has the special shopping cart icon on their AdWords ads. It looks like this:
Google AdWords Ad
After a few minutes of tracking down a site that had an AdSense ad for Dicks Sporting Good, I was unable to verify that Google is placing the checkout icon on the AdSense ads. Here is an ad I pulled from one site.
Google AdSense Ad
I was wondering if anyone has seen the icon on a contextual Google AdSense ad?
There is speculation at WebmasterWorld that this is a limited test.
Forum discussion at WebmasterWorld.