"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.