In the way of college admissions interviews, I suggest that you wear something comfortable. In the way of solid advice though, I can't offer too much. I wore a nice collared shirt and a good pair of cargo pants. One of my very good friends wore a business suit to all of her interviews. Both of us, I am sure, will go to a college. Therefore, casual is good, business is good, so choose whatever you feel will let you best concentrate on the interview.
The key to the whole process, if there exists such a thing, is confidence.