If you were one of the lucky ones to snag a 3G iPad 2 and you were also one of the lucky ones to snag an AT&T Unlimited Data Plan with your original iPad, chances are you're going to want to move that Unlimited Data Plan over to your NEW iPad 2. Here's how:

  1. Fire up your original iPad and go to Settings-Cellular Data and tap View Account – Log in with your email and password for your AT&T account
  2. Note the Cellular Data Number (your iPad's phone number)
  3. Then go to the Settings ->General->About screen and jot down your IMEI number
  4. After you get your NEW iPad 2 all setup go to the Settings ->General->About screen and jot down both your NEW IMEI number AND your ICCID (MicroSIM card) Number
  5. Call 1-800-331-0500 and wade through the prompts (press zero) to speak to an AT&T rep
  6. Explain that you want to move over your iPad Unlimited Plan to your NEW iPad 2.
  7. They will ask for you to verify your account address and then ask you for the information above from your NEW iPad 2.
  8. After they are done moving the account over, turn off your iPad completely and boot it back up. You should then do a test by turning OFF WiFi and trying to connect to the internet via your 3G connection. Done!

UPDATE!

OR

You can do it yourself

AT&T has put up this page allow you to update your device information via the web (Thanks Jack for the link).

 

They warn against just swapping MicroSIM cards!