An unlocked phone is simply one with all features activated and unlimited as to cellular provider. It is, obviously, the most desirable set up. Service providers often customize (limit)a phones features as well as limiting itsuse to their network. This is done to insure that you purchase a new phone or get into a long term contract every time you either get a new phone or switch providers.
The phone you are considering is a GSM phone. GSM is the prevailing system worldwide except for the US, we have an oddball mixture of analog (going obsolete) CDMA and TDMA and some GSM. T-Mobile has been the major leader in GSM service in the US (it is a division of Deutche Telkom) although Cingular has been getting ito the GSM game. It is probably only a matter of time until the others follow suit, although it is a major investment to change as all the cell tower electronics have to be changed.
You should be good to go with T-Mobile and probably with Cingular, all you need is a activated SIM card. If you travel internationally the big bonus is that the phone will work in most countries of the world just by turning it on. You do, however, have to pay international roaming charges (0.99 in Europe and $1.49 in south America) but anybody can reach you just by calling your US number. I love that feature on my T-Mobile phone.
I'd really like to purchase a Sony Ericsson k800i camera phone because of the great 3.2 megapixel camera it has.
However, no U.S. carrier carries the phone.
I'd have to buy it on eBay as "unlocked".
I currently have a cellphone with Verizon Wireless, but they say they can't support the k800i.
I hear T-Mobile can.
I've never had an UNLOCKED phone before.
How would I activate it with T-Mobile?
And is it true I can just buy a T-Mobile sim card with PREPAID minutes and use the k800i that way?
Would I be able to have internet access?