Want to get an idea of where an Italian surname comes from? Here is a fun site that will tell you how many families there are in Italy with the given surname, and above all, what its geographic distribution is.
Open the link given above, insert the surname in the field marked "cognome," and you will get the number of families and how they are distributed over the Italian territory. If you are not sure of the names of the Italian regions indicated, below is a map of Italy that shows them.
Note that some distributions may be misleading in terms of the ultimate origin of the name. Because of massive internal immigration (mostly from the South to the North, and to a certain extent Lazio, the area that includes Rome), some southern names may have a significant presence in Lombardia and Piemonte in the North.
There are other features relating to genealogy, but most require a knowledge of Italian.