Iphone on Tmobile
More than likely it will be a data plan specifically for the iPhone at $30 a month.
Unlocked i-phones are very common
Yes you can use an unlocked iphone on tmobile(cuz its GSM) but what everybody else is failing to mention is that you wont be able to use Tmobiles 3G network bc the iphone doesnt have the 1700mhz band built in which is the band Tmobile uses for their 3G...but you can still use EDGE which isnt much worse in my opinion and experiance