http://faqomatic.sourceforge.net/
The Faq-O-Matic is a CGI-based system that automates the process of maintaining a FAQ (or Frequently Asked Questions list). It allows visitors to your FAQ to take part in keeping it up-to-date. A permission system also makes it useful as a help-desk application, bug-tracking database, or documentation system.
http://www.devscripts.com/category.php?stId=111
Perl Knowledgebase System Scripts
http://sourceforge.net/projects/phpsimplefaq/
Built on PHP and MySQL, PHP Simple FAQ is just that, a simple, easy to use and administrate FAQ system for websites. Completely text-based and multi-lingual, it can easily conform to any web site since it works off of just one page.
http://www.nukedweb.com/phpscripts/faqbase.php
FAQBase allows you to set up an FAQ system for your website. This very flexible script supports multiple categories, a search function, and on-page admin links.