Update: Still haven't heard from AT&T, but we just rolled back into Chicago at 5PM CST and we can't connect on either EDGE or 3G. Let's hope things get better, and soon.
Update 2: According to AT&T, a power failure in Bloomfield, Michigan is the culprit, and techs are working around the clock to get everything back up in the Midwest. We're told rebooting phones may help -- it didn't do anything for us, but it might be worth a shot.
Update 3: It's back up, at least in Chicago. How'd everyone spend their day off-grid? We mostly threw the sad face at our NO SERVICE display.
[Thanks to everyone who sent this in]