AT&T says it will contact customers about the delay via SMS or email or the new date when they can expect to receive their Samsung Galaxy S III. Until supply catches up with demand, AT&T expects order fulfillment within 10 business days because of "Manufacturer Supply Constraints". AT&T is offering only the 16GB model of the phone for $199.99 after a signed 2-year contract. While the carrier won't be receiving a 32GB variant to sell, it is promoting the sale of a 16GB microSD card and will be the only carrier to receive a red model of the handset.
source: AT&T via Phandroid