After a period of beta testing Google is rolling out AdSense for Mobile in 13 countries: US, England, France, Italy, Germany, Spain, Ireland, Russia, Netherlands, Australia, India, China, and Japan. Much like AdSense on the desktop, it’s aimed at publishers and site owners and intended to extend Google ad penetration farther into the mobile Internet.

The idea here is that available monetization will encourage mobile friendly site development. There are a number of other mobile ad networks (with more on the way), including Third Screen Media (owned by AOL), Medio’s MobileNow network, Yahoo Mobile Ad Network, Ad Mob, Enpocket (bought today by Nokia), among a few others.

Could your website be easily transferred to a mobile friendly format, would it justify the cost?