Does iPhone 3GS work with Tmobile in the US?

[robrichards]

Wife ordered an iPhone 4, want to sell her 3GS.



I have a friend who wants to buy it, but he is on Tmobile, so want to know if we just out in his SIM card, will it work?

I know it will probably work for calls, but what about data?

 

[OhBoy88]

It has to be unlocked for it to be used. Data would be 2g & 3g in some areas