If you forget your password, you can click on the 'Forgotten Your Password' link on any page that requires you to fill in your password.

This will bring up a page where you should enter your registered email address, and an email will be sent to that address instantly, with instructions for resetting your password.

If you no longer have the emaill address that you registered with, send an email to [email protected] and include your username and your old email address.