How do users "claim membership types"?  In the "Admin Panel Manual", under "How to Grant/Refuse membership that has been claimed by a member?" it says:

"Members can claim free subscription unlimited membership types."

How do users get access to these other types of membership??

I have defined all sorts of different membership types (for testing purposes), but the ONLY memberships shown on the "Upgrade Your Membership" page (http://romeobox.com/member/payment_selection.php) are the current membership and "Gold".

Anyone know how to do this?  Thanks!