It took about 50 minutes. First they offered me to ask questions about the company and the position. I had several questions written down (e.g. What steps does AT&T take to go green?) so that part took about 10 minutes. After that, the interviewer asked me questions about how I did or would handle certain situations. E.g. how did I handle a collegial conflict in the past? Or I needed to give an example when I faced great adversity. This part took about 40 min. Too bad I wasn't prepared (with written and practiced answers) so that my interview would have been smooth and perfect. I learned a ton from this interview.