I went to an interview today and here are some general ideas that may be used at your school, too:
-What you know about the PT field and current issues in the field (APTA, direct access issues, DPT, etc.)
-Why you want to be a PT (other than "helping people," which is a common theme - I hope)
-Why you would like to come to this school
-How you will deal with a heavy class load and other responsibilities
-Personal questions (can't really prepare for these but IMO these are the easiest to answer because there isn't a specific answer they are looking for, these are more about your personality).
Hope this helps - good luck and let us know how it goes!