DocuPress for WordPress: Documentation Plugin
Plenty of product developers use WordPress to share FAQ and useful info with their customers. DocuPress for WordPress is a handy plugin that lets you create an online help site for your product faster. Once you install the plugin, you can add articles and organize your documentation into collections.
DocuPress makes it easy to provide relevant content to your customers to answer their questions about your products. It comes with a custom widget to display recent articles with randomization. This is a free script.