Do Content Management Systems really work?
My answer to Do Content Management Systems really work? on Ask MetaFilter
Have you considered trying a Wiki? In my experience, the more permissions / workflow / etc you have in a CMS the more likely it is that people won’t use it. Wikis may be a little unconventional but the barrier to entry is fantastically low and they can work extremely well (I like MediaWiki or TaviWiki myself).
I’m very skeptical of the idea that the people who update an intranet should be limited. If you have an employee who can’t be trusted to edit information on an intranet, why did you hire them in the first place? In my opinion the presence of a revision log should be enough to deter any abuse—if someone screws up, just revert their change and have a word with them about it.