Dozuki - Dozuki is a web-based tool for creating and distributing step-by-step documentation.
HelpSmith - HelpSmith is a help authoring tool to create CHM HTML help files, manuals, and PDF documents.
DocGen - Static website generator
FastHelp - FastHelp is a Windows Help File Generator that produces online and offline documentation.
openSourceCM - Web-based legal document processing and contract management
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.