Dear MBALA2009,
There is no norm or preferred timing for school visits. I think it is nice to visit prior to submitting your application for a couple of reasons. First, and most importantly, it allows you to incorporate what you learn into your essays. Or, on the flip side, your visit might result in you deciding not to apply, saving you some time, energy and money. Secondly, the school gets an idea of who you are which should enhance your application (assuming you make a positive impression).
If you cannot get to campus prior to submitting the application, it will not hurt you. It is still important to visit for you so you can make an educated decision on where to attend. Many applicants tie a campus visit and their interviews together, which is a great thing to do if you have to travel to campus. However, if you are local or geographically close to the campus, then I would say visit prior to submitting and again when you interview.
Best of luck,
Lisa
