The dialling code for Italy is 39 and the city code for Milan is 02. The city code is an integral part of the number and must always be dialled. Toll-free (free-phone) numbers, known as numeri verdi, start with 800.
Italy uses GSM 900/1800, which is compatible with the rest of Europe and Australia but not with North American GSM 1900 or the Japanese system.
There are no roaming charges within the European Union.