If your family is a U.S. military family - active duty or retired - be sure to check out the website for the USO in Italy (www.uso.it).  You will be amazed at what they have to offer you in the way of discount tickets, private tour guides, pick up and return to the airport and cruise pier, hotel reservations, packaged deals, and all kinds of wonderful stuff, including luggage storage and an Internet cafe.  The USO office in Rome is located very near to St. Peter's Square and the Vatican.  It is an awesome place with wonderfully helpful people.