Just like previous Lumia devices Lumia 920 and 820 have received official availability map from Nokia. As of now it doesn’t show much, other than some countries missing like Canada.
As of now Nokia has not said anything about the availability of Lumia 820 or Lumia 920 other than Q4 2012.
http://www.nokia.com/global/products/phone/lumia920/availability/
http://www.nokia.com/global/products/phone/lumia820/availability/
UPDATE
As of September 9 the availability list has not been present on Nokia’s site anymore.
