Things I should know before I buy a used Iphone 4.

[Grimreaper]

Hi. My friend is going to sell me his iphone for in a month or two, and I just want to make sure I know what I'm getting into. Here are some details about his iphone: It's an iphone 4, 16gb, Runs on ATT network, not jailbroken.
After he sells it to me, I plan to get a micro SIM and use it on the ATT go phone service. At first they said that you couldn't use an iphone on the go-phone service, but there are plenty of youtube videos showing people putting ATT micro sims in there iphone and they can use it on the go phone plan.

Anyway, Should I know anything before I get it? I heard someone say it is not jailbreak-able If it is on the latest IOS. Does that just mean on the latest update? Should I just tell him not to get the new update when it comes out or what? After he de-activates it, will he take the sim out, or just de-activate it and leave it in there. Because Somewhere I read that you need a SIM card card remover to remove the sim from the iphone, not sure if that is true, But i don't want to mess around with that.
And will his itunes account still be active on the phone after he deactivates it, will i just be able to make my account no problem? If i make my own account will I still be able to keep all the games and apps he has on there if I have my own account? Anyway, please answer these questions and add other stuff If you want

 

[chunky]

If its on 5.1 or 5.1.1 then you can jailbreak an iPhone 4 as tethered or semi tethered.

If its on 5.0.1 then use the latest version of redsn0w to jailbreak un tethered.

Don't AT&T now offer unlocking ?

I'm in the uk so I can't really advise.

In the Uk all the networks offer payg contracts and unlocking for a fee if on payg or normally free if on a monthly contract.

 

[bbrks]

I would suggest to unlock that iphone first, AT&T would do it, if it's out of contract and in good standings. After that, you can do what ever you want. And yes, I hope it's on IOS 5.0.1. because of the untethered JB.