Here’s a new twist on mobile advertising and social networks: Virgin Mobile (NYSE: VM) is launching a Facebook application today that will give customers, who participate in its Sugar Mama advertising program, a new way to earn up to 75 free voice minutes a month. Up until now, the Sugar Mama program gave users free minutes when they watched a commercial and answered a short survey online. But the “Fund My Phone” Facebook application now also earns users minutes when they get their friends to watch ads too. This way, Virgin can expand the audience (of what is probably like-minded individuals) without having to sign up more subscribers to the program. Currently, about 700,000 of Virgin’s five million subscribers have signed up for Sugar Mama.

How it works: A Virgin subscriber adds the Facebook app to their profile page, where friends can see it. The app encourages friends to watch commercials to help them pay for their wireless phone. When friends click on the application, a Sugar Mama ad or other piece of content begins playing for them to view and rate. Advertisers include Xbox, Diet Pepsi, Subway, U.S. Navy, Sony (NYSE: SNE) Pictures and Sony Music. The subscriber then earns six minutes of airtime as soon as the first four “views” by Facebook friends are credited. After the initial viewings, the customer receives one minute of airtime for every four views by their Facebook friends. I can imagine if a girl really wants to talk to a boy and he’s out of minutes, this would be a small price to pay. If it’s any indication, Virgin has given away 26 million minutes of free airtime since Sugar Mama was launched in 2006.