How do I change my keyboard layout from American to Italian since I live and use the Italian keyboard

Haven heard a bit of the ubuntu operating I decided to try it out on my Acer Aspire one netbook by installing it yesterday. I am really impressed so far except that the keys in my Italian keyboard now functions in contrary, that is functioning like an American keyboard layout. All efforts to correct it since yesterday to align the keyboard with the keys on the keyboard has been unsuccessful. I really need urgent assistance because its makes me very uncomfortable.

In summary I want to continue with the operating system in English Language, with the keyboard layout in Italian.

Thanks for your urgent response.