Ya sure you can use your t-mobile sim in any other phone only if it is unlocked one or else already locked with t-mobile else if the phone is locked to some other network provider then it wont accept your t-mobile sim until you unlock it ...You can easily unlock your phone through online providers like Unlock-Zone.com here they are rendering network unlock code for all mobile models at reliable cost .,You first check that whether the code is available for your mobile model ,country and network provider .If yes then pay for it and unlock the phone then freely use it with t-mobile sim ..