The night before the interview they offer a dinner, which I highly recommend going to. This is a chance for you to talk with the program director, teachers and students. I feel like it allowed me to develop a relationship with everyone prior to the interview, and helped relieve some of the stress on interview day.
The interview wasn't stressful at all. Its two different interviews and each one is a panel of 4. The questions I remember them asking are 1) Name a time when you faced an ethical dilemma, and how did you solve it? 2) Name a time when you wanted to change something, but were met by people who didn't agree, how did you convince them? 3) Why Wisconsin?
The rest of the questions were about things on my resume, and for me to elaborate more on it. Talk about the pros and cons of some things.
Overall, you shouldn't stress too much about it. Just relax, and be yourself.
Goodluck and keep us posted!