If you're going for tourism reasons (ie no business) you don't need a visa for stays of up to 90 days. Italy is one of the Schengen agreement signatories and the same entry rules apply across all 25 of them. You don't need a visa to cross from one Schengen area country to another (they've mostly disbanded border crossings). However it's still advisable to get an entry stamp in your passport, to prove that you haven't overstayed the 90 days - this is especially true if you intend to leave the Schengen area from a country different to the one you entered (they'll have no idea how you got there).
Have you seen the WorldNomads.com travel tips for Italy? You might find them useful especially for a first time visitor.
Enjoy your trip.
Phil at the safety hub about 5 years ago