Going To Italy

:unsure: Hi,
I don't understand all the technology. I am traveling to Italy next week and want a GSM phone to be available to our babysitter to us, or for us to call her.

I need to purchase an unlocked European GSM 900/1800 phone. I have found some on ebay. And I understand I can buy a prepaid SIM card for use in Italy. But how do I get a phone number for the phone? Do I need to get service with a carrier in addition to the SIM card? Or does the SIM card give me a phone number? I assume if I need a service provider to activate the phone and give me a phone number there will be an activation charge and maybe have to sign some contract??

Can I buy a prepaid vodafone sim card here in the US?

Any advice, instructions would be most appreciated!

Thanks,

Dawn