Ok, so it's a rumor thus far, but here are a couple articles that make reference to it:
However, a source talking to Nokia For Us says the phones are coming to AT&T, available in stores Nov. 2.
Joining AT&T sometime during the first week of November is T-Mobile, which will supposedly carry the lower-spec 820, and Verizon, which the source said is set to get a version of the 920.
http://www.techradar.com/news/phone-and-communications/mobile-phones/rumor-nokia-lumia-820-and-920-coming-to-at-t-nov-2-1094943
The date is a bit odd as it falls on a Friday. AT&T as far as we know always release phones on Sundays and they have been quite consistent in that recently for the last few Windows Phone launches. Why the change if true? Perhaps to get the phone out as early as possible but also maybe they are timing it with the end of BUILD 2012, which coincidently ends on the same day.
T-Mobile is expected to launch the Lumia 820 during the same week and later Verizon will launch the flaghship Lumia 920, hopefully in that fireball Red.
http://www.wpcentral.com/rumor-att-looking-launch-nokia-lumia-820-920-november-2nd