From Expat Talk, here it is in detail. I’ll make sure I know where each step is supposed to take place, since it’s a little vague, but these are the essentials:
1) Go to Questura
a. Within 8 days of arrival
b. Bring passport
c. Receive Dichiarazione di Presenza (Declaration of Presence)
2) Go to Comune (or is the Anagrafe?)
a. Bring Dichiarazione di Presenza from step 1
b. Bring copy of Circolare 32 – just in case
c. This starts the procedure to establish residency
3) Wait for visit from Vigili (aka police) at your local residence
a. This takes about 2 weeks
b. If police arrive at your residence while you are there, they will give you a “residency certificate” verifying that you do in fact live at that location.
c. If police arrive at your residence while you are away, they will leave a note indicating that you can respond at the police office within 24 hours. If you are able to make this deadline, they will then give you your “residency certificate,” otherwise this step restarts and you will have to wait about another 2 weeks.
3.1) Go pick up residency certificate at comune (anagrafe)
4) Go to Comune
a. Bring Citizenship Packet (aka vital records, apostilles, translations, etc)
b. Leave “residency certificate” and “Citizenship Packet”
c. Receive “printout receipt” indicating that your application for citizenship is being processed.
5) Go to Poste Office (or is it the Comune? or the Questura?)
a. Bring “printout receipt” from step 4
b. This is where you apply for your PdiS – attesa per cittadinanza (Residency Permit while awaiting citizenship)
6) Wait for arrival of both PdiS as well as citizenship notification
a. Either one can come first
b. Wait time varies for both (2 months to 1 year)
c. Dance a jig once official notification of italian citizenship arrives