What is the time frame, i.e. how early? Personally, calling schools before applying just to tell them that I adore their institution is just not my style. Doing so might even backfire if you start asking questions that are easily answered by their website, brochure etc. and might give the impression that you don't know how to navigate basic research. Though attending an open house, or the like, wouldn't be a bad idea. Remeber, you are one pile of papers in a sea of applicants. n my opinion, make your enthusiasm for their school known to them on their secondary application - I think that will make a more lasting impression, and they can refer back to that as opposed to trying to recall a prior conversation. Also, if you do call the schools, be extra nice and pleasant to everyone you speak to. A couple of people that I have talked to from my school who are now in various dental schools said that they discovered the secretaries often carry a lot of weight with the powers that be...