Netflix doesn't allow you to download movies in the sense of saving them to your hard drive so you can watch them when you're offline. However, the Netflix subscription model does allow you to stream and watch movies whenever you want to. If you want a copy of a movie, you really need to buy the physical DVD, or to enter the murky world of illegal downloads. This latter is extremely inadvisable as breaking copyright rules is illegal in the UK and has potentially unpleasant legal consequences.
Visit the Netflix website using the link in "Resources" below. Click on the "Start Your Free Trial" button.
Select "Start Your Free Month" in the next window. Now enter your personal details and choose a password. Click "Register" and you'll land on a page asking for your payment details. The debit or credit card you use must match the name you've registered with. You can also use a PayPal account for payment.
Choose a movie to watch by visiting the Netflix home page and signing in with your registration details. You can select from displayed popular titles or search for films by name, actor or genre.
Select your film by clicking on it. The first time you download a film, you'll be prompted to enable protected content. You'll also be prompted to download the free Microsoft Silverlight plug-in if you don't already have it. Then your film choice will load and start playing.
If you decide Netflix is not for you, cancel your payment during your free month and you'll pay nothing.