For foreigners in Italy, fishing requires:

1) a provincial licence, which can be easily obtained and it is valid all around Italy for three months: it costs € 8.52 . You'll be given a form by which you pay at the post office and the receipt is your licence. We may provide you with the form!
2) the FIPSAS licence, which costs € 21.00, in case you fish in places "belonging" to Federazione Italiana Pesca Sportiva. Most of the rivers have a section reserved for FIPSAS. You'll be given a form by which you pay at the post office and the receipt is your licence. We may provide you with the form!

3) There are places where you need a particular licence: when you arrive you ask around and they will advise you about the place where to apply. The list of places where you need licences is on www.pescambiente.it
The flyfishing website is www.pipam.com A list of places with some details, in italian, where you may flyfish is at www.pipam.com/pipam/dovepescare/Italia_mod/