Login Forms have perhaps the most variety out of all different kinds of web forms. How close to the Login should it notify new users to register? Extra features like forgotten password links or cancellation buttons. Should it open in a new window or pop up in a modal window. While you decide what would best fit your website, here are some examples that should give you ideas on how you should make your own.
There are also some resources and tutorials after the examples if you need help making login and registration forms.