You can deactivate your account temporarily by going to the Account Settings page, which can be found under the "Account" tab in the upper-right portion of the screen when you are logged in. At the bottom of the Account Settings page is the option to deactivate your account. If you do this, all your information will be inaccessible until you reactivate. It will be as though your account has been deleted. To reactivate, simply log in at any time.
Getting rid of your account permanently requires submitting the form found at Facebook's Account Deletion Request Page. Follow the instructions there and then wait for confirmation. Facebook's standard is to wait two weeks before actually deleting your account. If you log in at all during this time, the deletion process is canceled.
Facebook provides email addresses where you can contact a real person. If you want your account deleted sooner, write to firstname.lastname@example.org and make a request. It may take several days to get a response.
Turning off or removing your Facebook account completely is a multistep process that requires care. While in the process, you must be careful not to log in to Facebook, which includes sites that use Facebook Connect. Facebook Connect is the service that allows third-party sites to access your Facebook account for information or as a universal login. If you log in through one of these sites, your deactivation or deletion process will be canceled.