Get online and log in to your Netflix account. If you haven't created an account yet, you don't need to pause it. You can simply wait until you're ready to start receiving movies before you sign up.
Go to the account information page. You can find this link to the right of your name in the top right hand corner of the page. Once you are there, look under account information for a link that says "Put Your Account on Hold." Click the link.
The next screen will tell you how this all works. Basically that you can put your account on hold for 7 to 90 days. At the end of 90 days, your account will reactivate and you will be billed. You must return any movies you already have within 7 days of pausing your account or you will be charged for them.
Select how long you want to put your account on hold for and confirm. You can still add movies to your queue, but they won't be sent to you. Log in at any time to reactivate your account, otherwise it will automatically reactivate on the date you set.