I was in Italy for a weeks holiday a couple of weeks ago. We went toured around Rome / Tuscany / Palma area.
We were actually in Pisa for about three hours. We saw the tower and did the photos, like everyone else. You can go up the tower, but you need to book tickets and they are limited.
http://www.opapisa.it/boxoffice/first.jsp
You can go round the cathedral if you like, but were a bit jaded by then as we had seen so many up until then.
Other interesting places near by include, Florence which was lovely, but incredibly touristy and expensive. Palma, which was a lot less touristy, and we had our best food here.