I've been looking into buying an iphone 3gs and unlocking/ jailbreaking it so that i can use it on the t-mobile network. At the moment i have a BB curve 8900 and i have the unlimited data & text plan thats 34.99 on t-mobile, i was wondering if i do buy the iphone 3gs, unlock/jailbreak it will i have to change my data plan or can i do something to get it to work on the bb unlimited one ?