While i was surfing to adsense blog i find this interesting news. A very Good news for all AdSense publishers. now if you're using google sites then you can put your google adsense ads on it. In order to allow AdSense ads appearing in your Google Sites, you'll find "Monetize" tab in the settings area. With this Monetize feature, it’s easy to place AdSense ads on a site’s side bar or page content.
As stated in Adsense Official Blog
If you're new to Google Sites, we encourage you to take it for a test drive today. After you've built out your site and ensured that it complies with our program policies, follow these instructions to add AdSense to your pages. You'll have the option to place ads in the sidebar as well as the main content of each page, and you can choose the formats that work best for your site. If you're not sure where to start, we encourage you to check out our optimization tips to make sure you're maximizing your site's revenue.