If you are not already familiar to it, you may find many answers at:
which is also free. A search result there will supply volumes of useful information to the researcher - just be sure to take your time on each page and gather as much information as you can. Also, there are excellent source citiations at the bottom of each page which can (and should) be copied and pasted into the Source section or each individuals' Profile while editing there. Use a variety of seach parameters and spellings to widen or narrow your results.
This is probably NOT the person(s) you are looking for, but since I had a moment I decided to do a quick search for "Francesco Magnini". The below is probably for his son or grandson:
"Italy, Toscana, Civil Registration (State Archive), 1808-1923," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/VR8F-QV8 : accessed 01 Sep 2012), Francesco Magnini, 1894.
Obviously, the below result may be Francesco's son David's marriage info, which may open other avenues of search:
"New York, Marriages, 1686-1980," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/F63L-C21 : accessed 01 Sep 2012), Francesco Magnani in entry for Davide Magnani and Rosa Vignani, 23 Feb 1884; citing reference , FHL microfilm 1570328.
Lastly, it may be that you have already used and exhausted the Family Seach files and others - in which case you are kind of 'brick-walled". If my info above is more basic than you need there is no harm in your saying so. ;o)