Get your taxes done using TurboTax

As a US resident, the money is taxable here and you won't have a tax form so you will need to enter the income. There are a couple of ways to enter the income. The easiest - it seems - is:

1. Open your return to federal income
2. Select retirement income
3. IRA, 401k, 1099-R, start/ edit
4. Select I'll type it in myself
5. Continue
6. Select Form 1099-R
7. Continue
8. Enter information
   1. select foreign address at the top
   2. enter 99-9999000 for the Federal ID number
9. Continue entering information
10. Done

Reference: The US - Italy treaty article 19.