Thanks to Microsoft's GDR3 update, Nokia can offer a Windows Phone 8 model with a 6 inch screen LCD screen, 1080 x 1920 resolution and a 368ppi pixel density. The update also allows the device to be driven by a quad-core 2.2GHz Qualcomm Snapdragon 800 processor. With a purchase of the phone, the Microsoft Store is offering $70 of free Windows Phone Store credit, a free flip cover and Halo: Spartan Assault. AT&T will give you $20 of Windows Phone Store credit, 50GB of cloud storage with AT&T Locker, and Halo: Spartan Assault.
Remember, AT&T's version of the phone limits you to 16GB of native storage, and wireless charging is not included. A 32GB model is supposedly on its way. For those worried about storage on the phone, there is a 64GB capacity microSD slot on the device. AT&T does have anexclusive on the device in the U.S.
source: AT&T (1), (2) , Microsoft via Engadget