Best Practical Solutions - RTFM: The RT FAQ Manager
RTFM is an enterprise-grade knowledge management tool that enables an organization to easily capture and share its employees' knowledge and wisdom.

Just as you use RT (the world's leading open-source ticketing system) to log tickets and resolve issues, RTFM lets you open, categorize and search for "articles." Like RT, RTFM lets your users contribute additional information to existing articles and makes sure that each article's full history is preserved for future inspection. RTFM makes it easy to quickly search the knowledge base and find critical information.