When I got my gold membership I sent in a money order and it was no problem at all. I just sent it to the address that Ken gave you.
If you go to the top of the page you will see the link Get a Premium, Gold, Dealer or Knifemaker Subscription. When you get to this information just click onBuy Now beside were it lists Gold Membership. It will take you to a page where first you will be aked to type in the User Name for your Bladeforums membership, then you will be asked to select the shipping charge. Select the last option Bladeforums Membership Subscription (No Shipping). Then go to the bottom of the page where it hasSelect payment type: . Select payment by check.
After you have completed the above procedure you will be given an order confirmation number. Just put that number on your note that you send with your check.
I hope this has been in some way helpful.