Do you want to use your mobile with other sim card which is locked with T-mobile ?..If it so means you can't do it .To use other sim card you should unlock your mobile .To get your mobile unlocked contact T-mobile service provider or you can get the unlocking service from an online vendor like WickedUnlock.com .After getting your mobile unlocked you can use it with any other GSM network .Sprint network service support only CDMA mobile phones .IF your mobile support both GSM and CDMA network only you can use it with the Sprint or sim card .