Ok i got an ipod touch and a blackjack 2 (AT&T). What i want to know is if i sell them both and get an old iPhone could i use it with the sim card that is in my BlackJack 2 so that i dont have to upgrade to an iPhone plan? I dont care if i cant use some of the features like edge or voicemail as long as it can be used to make phone calls, unlimited txts, and act as a jailbreak Ipod Touch. I search the forums and found a few posts saying that if you unlock or jailbreak the iPhone it will accept other sim cards. Is this true?