Orca Scripts: Ringmaker
   Allows you to host a full-featured webring on your site using PHP and MySQL.
   http://www.greywyvern.com/orca#ring

Ringlink
   Information and download page for Ringlink, an open source CGI Perl web ring program. Also includes directories of individual rings, ring systems, and resources for ring owners.
   http://www.ringlink.org/