Last year, P. Diddy was the launch pad for all new artists trying to make it big. Now, everybody who’s anybody knows that “The O.C.” is the surest way to stardom in the music business. Puffy who? Case(s) in point — the Killers, Keane, Phantom Planet, Modest Mouse, the Walkmen. Adequate amount of musical talent, some pop appeal, but the big mother-ship VIP pass to everybody’s stereos is the luck of being featured on the “The O.C.” soundtrack. Yeah you’ve got Mischa Barton and her perfect hair, plus lots of plot twists in the mighty adventurous California town, but “The O.C.” does nothing better than exist as the biggest portal to promoting “the next big thing” and major comebacks (think Beck). What’s better is that this indie talent hothouse launched not one release but four. That’s right, four big fat soundtracks housing opportunities for artists that would otherwise go unseen on MTV radar screens. Got a band in your garage, some dreams of becoming a rock star and not enough cash to do it? “The O.C.” is open-armed and waiting for you.