I disagree with the credit card suggestion. Most US cards will charge 3% per foreign currency transaction. Using the ATM to get cash is probably the best way to go.

re: using cash instead of charging -

It is cheaper per transaction if you withdraw the maximum from the ATM each time. Also, especially in Italy (if my 2001 experience holds today), most merchants preferred cash and offered cash discounts, presumably to avoid reporting for income tax purposes which I understand is a national pastime in Italy.