Now that devices like the Nokia Lumia 900 and the HTC Titan II have joined the AT&T ranks, the carrier has brought their Mobile Transfer app for the Windows Phone platform.
The AT&T Mobile Transfer app allows you to wirelessly upload 2GB of contacts, photos and videos from old phones to AT&T servers. You then have 7 days to retrieve the data onto your new device.
Along with Windows Phone, the application is also available for Android, iOS, BlackBerry and even for feature phones. You can check out the full list of compatible devices on the AT&T website.
To get started with the service simply text TRANSFER to 6583 and you will be directed to download the specific app for your respective platform.
source - AT&T