As a director of a small ISP in the UK, spam is something that should be fought tooth and nail.
It would greatly help the anti spam industry, to send the mail (with a copy of the header informatio) back to your internet service provider with a request to blacklist that address. Remember that the 'From' address is usually not valid and only the header information can provide the ISP with a trace of the spam origin and a unique ID which is then put on an international database. Of course I am not sure if the Italian providers are as keen to deal with spam as UK providers but it is worth a try.
One golden rule is NEVER respond to spam mail as that confirms that your email address is live and working hence it will stay on the spam list. For example many of the virus hoaxes mails that go around are a way of picking up valid addresses for spam lists.
Also, you can try spamcop.net to report spam as well
ABUSE@NA.nic.it and CC
info@nic.it in Italy. Of course with some email programs you can block a particular address via your spam filter but these are not always effective; better done on the server.
Francis