it's currently available for pre-order! It's supposed to be released on Sept 17th. It's not exactly the instant gratification of buying The Avengers right now, but it's at a discount atm. I haven't checked out how much it will be on itunes (mostly because I'm on Linux most of the time). I've been waiting for the PBS airing, but I know that I'm going to just want to have it!

http://www.amazon.com/The-Hollow-Crown-Complete-Series/dp/B00DQN6IOK/ref=sr_1_1?ie=UTF8&qid=1377801547&sr=8-1&keywords=the+hollow+crown