Boost Mobile said today it is launching a mobile advertising platform to target the youth-oriented MVNO, owned by Sprint (NYSE: S) Nextel. With the help of mobile advertising company Amobee, the first ads are expected to appear today featuring information from Fox Searchlight Pictures’ upcoming release of “Street Kings.” Later, ads are expected to include commercials for Acura’s new 2009 TSX. What’s interesting is that Boost said its 4.6 million customers, who are mostly under the age of 30, will automatically start seeing the ads on Boost’s homepage and storefront, but they’ll give the customers the option of opting out by calling customer service. That might come in handy when the ads start appearing in other applications and in messaging, which is part of the plan.