As of December 7th, 2012 the following works on 12.04 and 12.10 (at least).
Open a terminal (Ctrl-Alt-T), an type:
sudo apt-add-repository ppa:ehoover/compholio
sudo apt-get update
sudo apt-get install netflix-desktop
This will install around 254MB of packages, mainly it will install
wine-compholio (a custom version of
wine that is able to run Silverlight) and dependencies. If
wine is not installed already you may need to agree to use Microsoft fonts (in the text mode window use arrow keys or tab to reach the red "ok" button in text mode when it appears). The download/installation takes around 15 minutes.
Then run the newly installed "netflix-desktop" application from the menu (or from the command line).
If something went wrong in the installation (third party links are involved), don't panic: netflix-desktop will detect that something is missing and try to reinstall it, if that also fails, start over.
When you run it for the first time it will initialize
wine and probably ask about installing Mono and Gecko wine packages (I accepted and installed them just in case).
netflix-desktop application opens up, login to your Netflix account.
The window will open in fullscreen, which is very elegant, but if you want to have control over the window press F11 right away to exit fullscreen mode. (It may also ask to install a Firefox extension --specially designed-- that makes fullscreen mode more friendly.)
Use Netflix as you would normally do.
It worked flawlessly in my Ubuntu 12.04 and 12.10 (I have a Core i7).
(As you may have realized at this poin, the
netflix-desktop is really Firefox 17 running on wine without menubars. Press F10 to gain control over the Firefox menu and navigation.)
Credits and references: This information was originally taken from http://www.webupd8.org/2012/11/how-to-use-netflix-in-ubuntu-through.html. Although this is a result of a campaign initiated by www.iheartubuntu.com in http://www.iheartubuntu.com/2012/02/netflix-on-linux-contest.html, resulting in this achievement http://www.iheartubuntu.com/2012/11/ppa-for-netflix-desktop-app.html (by Erich Hoover) which also contains a link for donations to support the development. There is also https://launchpad.net/netflix-desktop
Bonus: By running this you have a fully functional Firefox 17 (Windows version) with working Silverlight that can be used to navigate other sites, by pressing F10 -> View -> Toolbars -> Navigation menu on the main window you can access any site and be able to use Silverlight.