So, I finally got one. I bought it on ebay, so no sim card. I ordered a tmobile sim card (picking it up tomorrow). The auction says it's unlocked, but I don't trust that. With no sim card, or only tmobile sim card, how do I tell the firmware version to unlock it? Also, I've seen threads about whether or not to use itunes for syncing. Will I be safe syncing my music and apps from my ipod touch to the jailbroken iphone once it's unlocked?
Finally, is there a way to tell if it's unlocked before I pick up the sim card tomorrow at the post office, or will it be more like... "put the sim card in and find out if it works?"
No, there's no real way to tell if it's actually unlocked, but you can just upgrade it to 2.2 on iTunes regardless and then unlock/jailbreak from there (I'm assuming it's a 2G phone)...
Okay, from how i understand it the baseband was upgraded in 2.2 so they are still working on an unlock? If so your best bet would be to find the 2.1 firmware, jailbreak and unlock, and then follow the instructions on upgrading and keeping the unlock. I'll post the link in a sec, and try to find out if 2.2 can be straight up unlocked.
Okay, so I'm going to assume that you have windows just because it's a more popular os. If so follow that link and all of it's steps. Now, supposedly it should work, but I did see a complaint on it.
Your best bet IMO is to use the search feature on this website, or even google the info, that you want to know.
This is another step by step method, but personally I would trust iclarified.