Rogers 8310 unlocked, How I can setup with ATT for full funcation?

Hello, I have a unlocked 8310 in Rogers wireless. I am moving back to Tennessee and want to use it in ATT or T-mobile. But I heard that it would not work with T-mobile. So the only option is ATT. I don't want to sign a contract with ATT because I am using Virgin mobile for phone calls. But I would like to have a pay as you go data plan to have my full blackberry email function. I don't do web stuff, no text message, but I want to get my emails instantly.
1. I know I have to rewrite blackberry system to be ATT system using Blackberry software. This one I know how to do it (download ATT file system for 8310 from blackberry web then flash it into the phone by desktop manager).
2. I don't know how to do service book and pin transfer. Could anyone tell me how to do it step by step?
3. If I buy a pay as you go plan from ATT, does it have option to add a pay as you go data plan for unlimited emails? I could not find information on ATT web.
Thank you very much!

Here another question: I just found out that if I am using a BB with ATT, I have to have a data plan. Because I don't need to buy a new BB from ATT, could I just sign a data plan without a contract?

You don't need a contract to change anything on your account, or in most cases, to start a new account.

The entire purpose of a contract is to provide a subsidy for your phone. If you bring your own, there's hardly a need to recoup a discount.

Oof, as for reassigning your PIN code, if you had a BIS account tied to your BlackBerry at any point in the past, it needs to be zeroed. Call the carrier that was hosting it, and have their tier 2 department clear your BIS account of your IMEI and PIN. Or delete the whole account. Then you're good to set up your BlackBerry on any other carrier.

Email on BlackBerry phones REQUIRES BIS service. $30 monthly. It's provided by RIM, not the carrier, so don't argue it.

Also, you don't need to change the software on the phone. In rare cases, manually installing the service books will do, but a competent tier 2 representative can do this over the air.

Thank you, Mr. Xiado!
So let me clarify what I should do:
1. no need to change phone's software system.
2. If I want to have email service on my phone, a data plan must to have.
3. I don't have to sign a contract because I don't need discount new phone.
4. I need to call my current carrier (which is Rogers) to aske BIS department to clear my phone's IMEI and PIN.
I googled found BIS means blackberry internet service.
Thank you very much!

By the way, unlimited email service in Rogers wireless is $15/month. Up to 10 email accounts. This is what I am paying now.

Just MAKE CERTAIN that when you get a new account set up, that you weren't "sold" a new phone, and that you don't have a contract.

It is NOT company policy to require contracts for lines of service started with customer owned and maintained equipment.

And it MAY be possible that AT&T's service books may need to be installed on the phone. The method of doing this can be located easily by looking up how to do it with a Storm. Also, the APN settings (for the TCP settings in Options) are available everywhere, even on AT&T's own forums.