For the AppleTV, which is my preferred Netflix hub, the steps are surprisingly simple. You would have gone through a similar process on the initial set up of your AppleTV.
How toGo into Setting>General on your Apple TV.
Scroll down and select Network, select your network to expand into the more advanced options. It is here that you will want to change the DNS setting. This number is what tells the Netflix server where you are located, by changing it the server will provide content based on where it thinks you are.
Select Manual Configure and enter the following number.
Preferred DNS: 190.014.036.090
If the preferred DNS is not working I have provided an alternate.
Alternate DNS: 109.123.111.024
And incase those are not working try these (thanks "anonymous" commenter):
After manually entering the DNS, navigate back to the General settings menu and select Restart. Once your AppleTV restarts you will be able to enjoy the catalogue of American Netflix.
And since you're in the settings moving things around, check out this post (Hidden Apple TV Features) for ways to get more out of your Apple TV.
Please note, these DNS numbers do expire from time to time. I will do my best to update them here so that you can keep your system up to date.
Updated Aug 1, 2013
You can also watch the American content on-the-go with the iOS app. Check out this post for the instructions.
If you are having problems, check this post for troubleshooting ideas.
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