It was a 3 session process. First session I had an interview with my potential boss. Second session I interviewed with my potential co-workers. Third session I had a phone interview with the regional director (the boss's boss).
The first interview was casual and was more of a conversation. It lasted an hour. The second interview was also casual and the co-workers asked questions to see how you would fit in. The third interview, the phone interview, wasn't really an interview at all and it was basically an opportunity for you to ask more questions.