First off, apologies if this has already been asked, I didn't see it in the similar threads portion. I just bought a iPhone 3g off craigslist and realized its on 3.1.3 (not unlockable) but I've heard since I'm on the AT&T carrier I do not need the unlock.. BUT I also heard I need to unlock the iPhone to avoid AT&T automatically adding the iPhone data plan to my bill. The iPhone is working and all, at the moment I'm just using it as an expensive ass ipod. just no sim card in it as of right now, and I do not want to put my sim card in it cause I heard AT&T does sweeps for smart phones. So basically my question is: Do I need to unlock my iPhone to avoid getting the iPhone data plan? I want to use the iPhone on just my unlimited messaging plan (NO internet/data, I'm going to use the iPhone for wifi only since it's pretty much all over my schools campus) Any help would be appreciated!