You have to buy an "unlocked" phone. I wish I had more info for you but I know u can't just buy any old phone as some online aren't supported with certain providers and some aren't even supported in the US (like the cool asian ones I always want!). I know cingular allows you to take any phone to them, but I'm not sure about your provider or if they'd charge a fee.
Not all cells use sim cards. I know providers like Sprint and Verizon don't use them (but I've never heard of cell one, is it new?) . I know a little about this because I really want a cool european cell phone because I'm bored with all the ones here in the States. Some things I know:
The phone (duh haha) has to have a sim card slot.
The phone must support the same standard your provider supports (in america, 1900 network)
When a phone is referred to as dualband, this usually means that it supports both GSM 900 and GSM 1800 networks; tri-band usually means GSM 900/1800/1900 support.
The place to start is with a GSM phone. Just as radios operate on different standards (AM vs. FM) and frequencies, so do cellphones. Two of the most popular cellular standards are GSM (global system for mobile communications) and CDMA (code division multiple access), each of which uses different frequencies.
So basically, GSM phones use sim cards (most of the time) and CDMA phones don't; for example Verizon and Sprint/Nextel don't use sim cards, and they are also on CDMA frequencies.
As AlliSwan said, the phone has to be unlocked, originally or factory. That basically meanns its not "tied" to a certain provider or region, so you can basically pop your sim card in there and it should work.
My friend went to the Phillipines about a year or two ago, and she bought the black Motorola Razr, before it was released in black here. She just put her sim card in it (she has T-Mobile) and it works fine.She still uses it today!
Also, finding a good unlocked phone can be expensive. Even if a phone you want is already out here in the States, companies still sell them for full price, sometimes more seeing as you're not buying it with a certain provider, who usually gives discounts with phone plans.
Heres a great website to see phones: http://www.gsmarena.com/
Once you select a phone, it tells you what Network it runs on (remember, has to be able to use 1900), all thee other specs, and links to sites you can purchase it from.
Hope this was of some use to you! Feel free to ask me anymore questions
Oh and, there is a way to unlock your own phone or a phone that is "locked" but some companies don't let you (cingular) or others charge a big fee, and I think T-mobile lets you after a certain amount of days. Here's another link : http://travel2.nytimes.com/2005/06/1...2f69&ei=5 070
that tells you about using your american cell overseas, but all the info is about the same on how to use an unlocked phone (just try to think backwards haha). HTH, and I didn't confuse you!
I'm really liking mine so far. One of the reasons I love it is b/c no one can tell I have it in my jacket pocket since it's so slim
That and it's got Bluetooth. I can't live without that headset!
My b/f works for Cingular, so instead of waiting for me to get off work he went ahead and took care of it all & paid for it as an early Valentines present.