I am writing a simple Q & A for my organization internal usage. It does not have to feature rich like SO. Something much simpler. How do I begin? Is there a script available I can use off the shelf?
This is advice for rolling your own only, I have no idea if something suitable exists.
I suggest that you start with deciding what data you want to store.
As an example, for each question, you have the question (title and text), the answers (text), and tags. You might decite to include more (users, dates asked), or less (removing tags).
Now, design the database schemas. Then write a really simple interface for browsing questions, and for adding a new one. The core functionality is done!
maybe this link points to an useful script
http://webscripts.softpedia.com/script/FAQ-and-Knowledgebase/Question-and-Answer--22256.html
You could install a forum? SMF (Simple Machines Forum) is a good one.
You should take a look in wikipedia API.
I now it's huge.
But it's very simple to install and use. You'll have simple and nice features.