Public Telephones:
Public telephones are available throughout Italy.  Either local or international calls  require the use of a phone card (Carta Telefonica) which  may be purchased at any newsstand, tobacco shop or "bar"(coffee shop).

Long distance Calls (Interurbana):
Both local and long distance call require the proper area code before dialling the number. Ex: to place a call within Rome you must dial 06 + phone number.
To call Rome from Florence : 06 + phone number; to call Florence from Rome : 055 + phone number. 
When calling a cellular phone, drop the zero of the area code, ex: 397 + phone number of the cellular.
To call USA or Canada from Italy : 001+area code+ phone number.

Country Direct Service:
From phones in major cities, to connect to a US long distance service, dial:
1721011 for AT&T
1721022 for MCI
1721877 for US Sprint
The numbers above work for Rome, Milan, Florence, Naples, Venezia, Torino, Catania, Vicenza, Livorno, Olbia, Bologna, Brindisi, Cosenza, Formia, Genova, Latina, Padova, Palermo, Perugia, Pescara, Pordenone, Pisa, and Trieste.
When calling from pay telephones, just insert the prepaid card. You automatically reach an operator in the country of destination, avoiding all language difficulty.

Canada can be reached by dialling 1721001.