Ok, I'm sure you get asked this a lot but...

[Efrdman2008]

Ok here is the deal, I am currently on an At&t Familytalk plan and I want an Iphone since my phone is breaking down after 4 years of age. I don't wan't to pay for the actual Iphone service so I decided to Jailbreak and stick my Sim in there. But from what I heard they can find out if you are using a Sim and Iphone that dont match up together and charge you for it.

So basically my question is... Is it safe to jailbreak if I don't buy their data plan?

I'm probably buying my friend's 3G upgraded to 3.0 if it makes a difference, Thanks for your help!

[StealthBravo]

You can just pop your sim in the iphone but AT&T will find out eventually. Your IMEI is registered with the network

[Efrdman2008]

You can just pop your sim in the iphone but AT&T will find out eventually. Your IMEI is registered with the network

Even if I never connect to EDGE/3G?

[i.Annie]

Change plans! That way they will never find out anything that you do!

Lol it might be difficult or inconvenient but I find using AT&T without the iPhone plan is a risk and can either void your warranty and/or your device will get blocked.

[Efrdman2008]

I would but I'm on a third line of a Familytalk plan, so that isnt going to work

[angiepangie]

Using your iPhone with a non-iPhone sim will neither void your warranty nor get your device blocked (at least as far as I know).

Just use your AT&T sim in. They can't force you to upgrade your plan or charge you extra unless you use data without a data plan.