Government officials insist on using their smart phones (especially devices like Blackberries) for official, as well as personal, business. When even the president of the United States joins this club, smart phones can no longer simply be forbidden because of potential security problems. So there has sprung up a growing market in secure gateways for users of smart phones, who deal in classified information. Corporations are also big users of these hardware/software combos that make it much more difficult for hackers to tap in (and take out anything). This kind of protection goes beyond encryption, to eliminating storing data along the way, or mingling with unprotected traffic.
So far, this approach has kept the smart phones pretty secure. Which is just as well, because such devices are the future of computing. Many people are shifting many of their computer use to the smart phone. Apple foresees fewer iPods being sold, as people use their smart phones for listening to stored music (and having ones less device to carry.) For military personnel, the smart phone is evolving into an administrative and combat tool. So the need for secure smart phone networks is going to grow.