google online for questions to ask any program and any program in your specialty, and questions related to what your career goals and how the program can help you with that
I think the NRMP has a list even
be sure to have a list of questions that you use, use that list to research the program beforehand to help you with asnwering the questions in my last post for the interview, to be sure you look like you have done your homework on the program (don't ask dumb questions that are easily found on the website), and to be sure that you then have questions left over that make you look smart and interested when everyone asks you that dumb dreaded question "what questions do you have for the program" over and over again
if they start the interview with that, you can weave in details about yourself saying, "Well, it's important to me to be ___ kind of doctor because ___, what opportunities for ____ training is there here?"
you can ask the same question to more than one person that day if it's intelligent and makes sense to get more than one view if you start coming up short on questions
I think there are threads on SDN where people ask residents/attendings what questions to ask, because the irony is as an MS4 you don't really know what is important for residency training
you don't know what you don't know
ask your specialty advisor/docs in your chosen field what sorts of things matter and what they wished they had known about residency training in picking a program that they didn't appreciate when they were going through the process, I had some surprising things come up
on the interview trail I even asked the residents and attending at the programs what they wished they had know and what they thought was important for an MS4 to consider that they wouldn't have thought of when they were in my shoes (they won't be as real with you as the above suggested group, but you will learn certain things about the program you wouldn't have known otherwise)