I'll probably get a Wind SIM. For Italy it's definitely the cheapest, and I'm planning to go there next year. Even for 3 euro/mth, 2MB isn't bad @ 0.015 Euro cents/kb.
Form Australia, everything is AU$0.01c/kb min for roaming...
Vodafone
http://www.vodafone.com.au/rep/coverage/go...g_os&ss=gprs_os
$0.01c/KB = $10/MB
Telstra
http://www.telstra.com.au/mobile/products/...ingoutbound.cfm
$0.015c/KB = $15/MB + 50c flagfall
Three
http://www.three.com.au/personal_dat...countries.html
$15+/MB - $7/MB on 3 partners.
Optus
http://www.optus.com.au/portal/site/smallb...nextfmt=default
$0.02c/KB = $20/MB