Electricity in Italy runs at 220V, 50Hz instead of the 110V common in North America. Nowadays, most small appliances (e.g. hair dryers) sold in North America are automatically built to handle both 110V and 220V. Check the instructions or call the manufacturer to verify that this is the case with what you wish to bring along for your trip. For all other appliances you may need a transformer. You may also need an adapter, since plugs in Italy have two round pins instead of the prongs usual in the US. Adaptors are very easy to find either before you leave (e.g. on-line, at the airport) or in Italy at an electrical supply store (look for a “Ferramenta”).