Big money has flowed to iPhone app startups that are helping people track the whereabouts of friends or find nearby restaurants, clubs or bars. The two most prominent players in the category right now are Palo Alto, Calif.-based Loopt -- backed by Sequoia Capital, NEA and others -- and Seattle-based Pelago -- backed by Kleiner Perkins Caufield & Byers, Bezos Expeditions, etc. Those are some...