Forums Moderators are selected by either the Webmaster or our Forums Admin, wayne_h. Generally they will contact members they think would make good Moderators. Also, current Moderators/Database Admins can recommended someone.
Database Admins are selected by either the Webmaster, or,ericcarlson, our lead DB Admin. DB Admins are usually contacted and chosen based upon their knowledge of a certain area or, as above, they can be recommended by current Admins. The Wiki Admins are chosen by either the Webmaster, or, our Wiki Admin ka3jjz.
You could also try contacting any of the above people and ask. Hope this helps