"Our mission is serving the military and their families," says Wayne Peacock, 51. How do you reach that widely dispersed constituency—many of whom are deployed—with sophisticated financial services and advice? By rushing innovation after innovation to USAA's 7.4 million members, thanks largely to an in-house developer team in San Antonio that feels as if it belongs at a Silicon Valley startup. Recent successes from Peacock's crew include a mobile app (for Android, iPhone, BlackBerry) that lets customers find, finance, and insure a car. And in its banking apps, USAA customers can snap a photo of a check to "deposit" it—with same-day access—into their accounts.