Google Checkout is the new service that will let you buy products directly from the Google ads. Here are some screenshots that show the new ads, the badge you'll see on merchant's sites, how do you place and track your orders.
Also see a video tour of Google Checkout and a presentation for online sellers. Google Checkout for online merchants is already live at https://checkout.google.com/sell.
Here's the logo:
Update: Google Checkout is now live.
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