I will be in Sardinia & Corsica this summer. I need a mobile phone
that I can use there with high speed data access (3G). I am assuming
that I will need one SIM card for Sardinia and a different SIM card
for Corsica (to avoid roaming). I am aware of the carriers that offer
3G in Sardinia & Corsica. I have the following questions:

1) Which carriers have the best 3G coverage in Sardinia & Corsica
(ideally I would like to see 3G coverage maps).

2) Would I be able to use a 3G phone as a data modem for my laptop
(using Bluetooh, for example) or would I need to purchase a dedicated
3G data card?

3) What would the rates be for data access & voice communications? Is
there a prepaid plan for 3G data?

4) Where is the best place to purchase the SIMs and/or 3G phones online?

http://btsitalia.net/bts_sar.htm

here's a list of available BTS for Sardinia.
Vodafone (OPI) and Tim have better coverage than other companies. Flat
rates available (maximum 500mb/month at 30? with vodafone)

Less coverage in corsica

You can use your mobile (better with a data cable than bluetooth) but
depends on which model you have.

I'm italian, I can help you further in finding cheap sim cards.

Available for further info after 8 may (a road trip into sicily with
my laptop, looking for 3g bts...)

So how did the hunt for 3G coverage go in Sicily - I will be there
next week and need to know whether its worth bringing my 3G kit.
Cheers