The postcode database is not free, as in beer, in some countries, like in UK, but it has always been freely available in Italy. On the 20th of September 2006 many zip codes have been changed, and Poste Italiane Spa, the national Italian postal service, stopped to give them for free.
Reading the Italian FAQ it’s clear that Poste Italiane is trying to create a monopoly through proprietary software. Such program, a stand alone application designed to be used only by a single user, runs only on Windows because of market share evaluations led by Poste Italiane.
So if you need to access Italian ZIP codes, and not just to make single enquiries through the Web interface, you have to buy that software, and you must use a PC Windows based.
I’m wondering if the Poste Italiane’s application runs on Wine..
I found interesting an English study stating that Public sector information holders keeping hidden information (raw data) cost the economy half a billion.