Can I use my u.s. cell phone with a different sim card, or do I need to buy an international phone? If so Where can I get one of these phone and do I buy minutes or do they come with minutes. I will be traveling to Italy after that so I need a phone that works in both countries.
Rosie,
If you have a T-Mobile phone, you should be able to get a T-Mobile prepaid SIM card for a couple of pounds. Check out the UK Web site: www.t-mobile.co.uk, and look at the pay-as-you-go phones. You can get a Samsung E1120 for 9.78 pounds; if you have a non-T-Mobile phone you can unlock, check out the "Free pay-as-you-go SIM" link.
Call T-mobile. See if your phone will work on there bands. If so, ask them to unlock it. The process takes about 5 minutes.
SIM cards are everywhere. Look for an 02 or vodaphone shop. Used 02 on our last trip, and worked fine.
You can even pick up the SIM cards at some grocery stores.
Rosie,
If you're with either AT&T or T-Mobile, you also might consider roaming with your home network. It can be expensive if you use the phone a lot, but for occasional use it's by far the simplest method.
Could you indicate which network you're with in the U.S.?
The first step is to determine whether you have a phone that works on European frequencies, which are different from North American frequencies. If you have an "unlocked" or a "quad band" phone, it probably works on North American and European networks. If you don't have one, ask around in your hometown for someone who knows how to unlock your phone, or look on eBay and Amazon.com. Once you arrive in London, you can purchase a pre-paid SIM card from Vodaphone, T-Mobile, and Orange. Each company has stores or kiosks everywhere. I believe that Carphone Warehouse is unaffiliated with any carrier, and has stores throughout London. It sells pre-paid SIM cards. Try these links.
http://www.carphonewarehouse.com/mobiles/sim-cards