Currently Being ModeratedJan 21, 2013 6:46 PM (in response to duhitsnicole49)
If you purchase an unlocked iPhone it will work on almost any GSM provider world wide.
Whether T-Mobile will allow you to use it on there network or not is a question for T-Mobile.
Currently Being ModeratedJan 21, 2013 7:04 PM (in response to duhitsnicole49)
If you're talking about T-Mobile in the US, they will be happy to take your money. Some features may not work as their network is not fully compatible with the iPhone.