There are two ways to join the club. If you have an account at the forums click on “My Profile” under your User at the top right after you log in there.
Then click “Edit Settings” and then “Subscriptions”. You can join there instantly if you pay through PayPal.
The other way is old school. Use the PDF attached, print it out and send it to the membership secretary with a check (or a cheque if you aren’t in the USA). He’ll make sure your account is credited.
If you have questions see the contact us links.