Support database

I am trying to find a good PHP/mysql based frontend to create a support
database where admins can post solutions to problems we have on our
intranet.

Like Moveable Type - or something like that - except for a technical
support database.

Can be simple, can be free or for cost, but search of docs and cross
referencing would be almost essential. I am looking for an 'off the
shelf' solution, or a framework for creation of my own system. Any
suggestions?

Thanks
matt