The easiest way is to click the unsubscribe link at the bottom of every newsletter.

Or you can log in and update your newsletter settings here.

If you are asked to log in, enter the email address the newsletter is sent to, along with your password, and select the 'Newsletter Settings' link in the left-hand navigation.

If you've forgotten your password so you aren't able to login, you can reset your password at any time by going to this page.