I'm kind of interested in getting Italian citizenship. It would be through my great grandfather, I have his naturalization petition, which was 3 years after his son my grandfather was born. How would I get the certified documents from Italy? Where do I apply?
Where do you live? You will need to apply at the consulate that serves the jurisdiction where you hold legal residence. Check with the consulate. An original petition may be sufficient.
As for the Italian documents, simply write to the comune where he was born (preferably in Italian). If you do not speak Italian, you may want to use one of the many templates posted here and in the template forum at www.italiancitizenship.freeforums.org
I believe you fall under the jurisdiction of the consulate in Houston--good news because that is one of the easier consulates with which to deal. Your best bet is to contact them directly to determine if your ggf's original petition is sufficient and then go about collecting the other documents.
London82, I wouldn't worry about your comune not responding if you don't write to them in Italian. I have lived in Italy for quite some time and have never come across a civil servant that couldn't at least read and understand some English. I would suggest that you go ahead and write your request in English but include as much information as you can about the ancestor who's information you're seeking, for example the name of his wife, parents, sisters and brothers or even cousins. If your ancestor has a common name, providing information about the family will help narrow it down considerably.
My own sur name is fairly common. I went personally to Italy to obtain my grand-father's birth certificate. The first comune turned out to be the wrong one. The administrator determined this when he started asking me about the names of my ancestor's siblings. Then he directed me to the comune of "my clan" as he called it, which was just six miles up the road. By the way, he only spoke little English but he was able to get the job done.
Giovanni is a really nice guy who is very successful at getting you documents at a fair price -- cheaper than the Web sites and services online. Many of us over at the Free Forum have used his services. I did and got documents I needed within a week.