I have Tmobile and have wanted an iPhone forever - I finally took the plunge and bought a used iPhone 4 that is jailbroken and unlocked (1.59 baseband, ios 5). I'm a Mac user and I've had an iPod touch so I know the basics, but I know zero about the whole jailbreak/unlock thing and I'm terrified that I'm going to accidentally lock the phone or something! I did a search on this sort of thing here but didn't see specific answers to these Qs - please forgive me if this stuff is already answered somewhere. If there's a great website or thread that covers all this I would love to be pointed in the right direction.... Short of that, I'm hoping someone here can answer a couple of specific questions: 1. I've looked around online a bunch but haven't found a good, clear set of directions for how to set myself up on Tmobile. Is it just as simple as putting the mini SIM card in and that's it? Do I have to manually put in any settings or anything? 2. The only way I can screw up the unlock is to update the software, correct? I assume an iPhone works just like an iPod touch in that when I plug the phone into my computer, iTunes will ask me if I want to update the software - it won't ever just go ahead and do this right (I'll always have the chance to say no?)? At this point I'm just paranoid about plugging it into my Mac! 3. Are there any other tips or settings or things I need to know? Thanks!