a-mac, if you are interested in many MB of data, the best offer is this one:
http://www.areaprivati.vodafone.it/1...y_senza_limiti
but it's not cheap, since it's 5€ per every day you use it (=if you don't connect you pay nothing).
Here I put a new sticky thread:
http://www.prepaidgsm.net/forum/euro...ata-italy.html