There is a Knowledge base template as part of the Fantastic 40 for SharePoint 2007.
The Knowledge Base application
template helps teams manage the
information that is resident within
their organization. The template
enables team members to upload
existing documents or create new ones
using Web-based content creation
tools. Items are tagged with relevant
identifying information so that others
can more easily find the documents and
learn from the collective knowledge in
their organization. The template can
be utilized in a 'top down' approach,
where a centralized knowledge
department 'pushes down' relevant
content to the rest of the business or
a 'bottom up' approach, where
knowledge is captured and shared by
all users as a normal part of doing
business.
Here is a guide to get them working on SP2010 (havent tested it though).
Grab it here
Or see them in action here