AT&T Phone Activation Instructions
For AT&T and Unlocked GSM Phone Devices - All you need to do is remove your sim card from your previous device and place it into your new phone.
If you are using a dual CDMA / GSM Blackberry phone such as the Blackberry Storm, Blackberry Bold, or Blackberry Tour - please refer to our Blackberry GSM Instructions.
For other CDMA / GSM compatible phone devices - you may have to change the network settings of your phone to work properly in GSM mode. These settings can generally be found in the settings -> options -> network settings of your device. From there you should be able to change the settings from CDMA to GSM.
You may need to download service books to your phone in order to get MMS and Internet features working properly. AT&T Should be able to easily these features working for you.
For Additional Support:
AT&T Customer Support Number - 1-800-331-0500
Need Additional Help? Contact Our Support Team