I was able to obtain an interview with USAA through my university's online job search and internship application. The interview process was well structred and went smoothly. The employer asked me the usual interview questions -- why should we hire you, describe a difficult situation, greatest strength/weakness, etc.-- and proceeded to also test me on general reasoning skills via a simple test. He was very polite and gave me plenty of time to think and respond. Nothing too out of the ordinary, but keep in mind this was for an intern position and not full time. He explained that if one passed this interview process he or she would be interviewed a second time at their facility. When I brought up the fact that I had already recieved an offer from another major company in regards to a time constraint, the employer seemed more interested in our discussion. However, it is hard to know whether or not this would have been the deciding factor as the interview had seemed to progress well before that was mentioned.
I believe that your best bet for obtaining an interview and hopefully an internship is to know your techincal skills as well as knowing proper social ettiquette and seeming enthusiastic and motivated. I would advise learning Java (any other programming languages are good too!) as well as having a firm grasp on mathematical reasoning and critical thinking. I would believe that you also need to be enrolled in or have graduated from a 4 year degree program. Good luck!