Batman Begins is sold out at Amazon (labeled as “Temporarily out of stock”). Best Buy will take your order online and will ship (if a local store does not have in stock).
The Dark Knight is sold out at Amazon (labeled as “Temporarily out of stock”). Best Buy will take your order online but won’t ship until mid-January.
The Dark Knight Rises is sold out at Amazon (labeled as “Temporarily out of stock”). Best Buy will take your order online but won’t ship until mid-January.
The Dark Knight Trilogy, with all three of Nolan’s Batman films are also sold out, but Amazon has a new stock date of Dec.25. Best Buy has some copies left in stores.
Keep in mind these store and disc searches were done from one zip code and online, so it is possible there are copies of The Dark Knight titles at local stores.