I was initially referred by a current employee. I got a call shortly thereafter from a recruiter, who went over some basic information with me. The recruiter was great and helpful, and not hard to get a hold of (like recruiters with some other companies).
After speaking with the recruiter, I had a "technical screen," which was basically a phone interview with a current manager familiar with the position. It took about a half hour, and the questions were related to prior knowledge of Excel and other software, and basic financial and accounting knowledge. This was a great time to ask questions of the current manager, to find out more about the position. The interviewer then reported back to the recruiter.
A day or two later I got a call to set up an in-person interview. There were at least a dozen other interviewees in the Rosslyn office - it seems like Deloitte does regular "interview days," where they interview many people for various available positions. I interviewed with three managers, who did 3 different interviews: a behavioral interview, case studies, and a general personality and fit interview. The first interview was a basic chance to show off accomplishments and past experiences. The case studies were short, with a paragraph-long situation followed by 4 or 5 questions. The point of this was for the interviewer to see my problem solving process and pick up on some technical skills. The third interview was more casual, and was more of a conversation about fit, career goals, and life at Deloitte.