Facebook is rolling out an extended distribution of the now 9 months old Facebook credits online exchange, making prepaid Facebook credits gift cards available in Walmart and Best Buy branches within the U.S.  Available in $ 5, 10, 25 and 50 worth gift cards, the now real-life Facebook credits are making their way throughout retail like FarmVille did throughout online gaming, only to local shelves. Reuters reports,

“No, you can’t use Facebook Credits to buy a six-pack of beer or a new iPod. The currency remains limited to use in the social games and applications popular on Facebook, where people can use Facebook Credits to buy virtual crops for planting in the FarmVille game, for example.”

Facebook has sold credits ever since early this year, but the arrival of the gift cards to the two national giants Walmart and Best Buy represents a landmark in the involvement of social media with the retail industry and customers’ approach to purchasing.

Facebook has over 500 million users with a healthy percentage of those being U.S residents, meaning that the intensively distributed gift cards will make a whole lot of Farmville buffs happy, and Facebook even happier. Furthermore, since a lot of people (surprisingly) don’t own a Facebook account yet, these will also gain the social-networking giant even more users and hence even more FB credit purchases.

This is the latest in Facebook’s retail partner takeover.  Amazon was another early integration for deeper recommendations.  Facebook’s platform is becoming more integrated with a number of retail systems, and they have a huge opportunity to be a leader in monetizing such direct channels between brands and consumers.   A number of startups like PayNearMe are finding unique ways to integrate retail with digital cash representations.