Assuming you already have a Netflix account:
1. Go to your TV and start up the Netflix application.
2. It should give you an option for selecting to activate your existing account.
3. A unique activation code should be displayed. Write that code down.
4. Use your computer and go to:
www.netflix.com/activate and enter the activation code.
5. A confirmation screen should tell you that your TV is now ready to view Netflix.
6. Enjoy.