1) As stated above, you
cannot use the iPhone 3G with T-Mobile's 3G network. You
can use either iPhone (EDGE or 3G) with T-Mobile's
EDGE network. Everything on either iPhone will work except for visual voicemail and 3G-related functions (3G higher quality calls and 3G data speed).
2) You cannot use either phone with T-Mobile, however, without unlocking it. For the EDGE iPhone, unlocking is something you can do yourself with software (Pwnage). This is discussed in detail in the sticky threads of this forum. For the iPhone 3G, today the only way to unlock it is to use a hardware device like the TurboSIM, which is also discussed in detail in this forum. The software tool from the Dev Team (who made Pwnage) is promised to be released in an iPhone 3G compatible incarnation on 12/31/2008, but they have stated that this will not support the latest iPhone 3G baseband, and so the timing for a working software unlock of a
newly purchased iPhone 3G is currently unknown.
3) Once you unlock the iPhone, if you did a software unlock, you can place your existing T-Mobile SIM in the iPhone, program in your APN, and it will work without any additional changes on your existing data plan, even if you have a Blackberry plan. If you did a TurboSIM / hardware unlock, then you'd be using the TurboSIM and it would be programmed (as I understand it) to your existing T-Mobile account.
4) The cost of early termination is $175, and you'll probably also have to pay for at least one month of service (about $100) and an activation fee ($36, I think). I'm not an expert on these numbers. But I think in total it comes out to about $300 over the price of the iPhone itself. I've also heard that AT&T demands the iPhone back if it's canceled within 30 days, but I have no idea how they enforce this (If this is true and they do, I think the enforcement would be that you've agreed in the fine print to pay the unsubsidized handset cost, which is something like $550 or 600). Here's another thread discussing that.
https://forums.macrumors.com/threads/555251/
5) It looks like you have either bumped this thread repeatedly or made new threads repeatedly on the same topic, which were merged by a moderator. Whichever you did, please stop doing it. It's extremely inconsiderate to our forum members. People here will be happy to help you, but they are not your paid tech support service.
