At a guess, sounds like you might want to check out the Role Manager plugin: http://redalt.com/Resources/Plugins/Role+Manager
The plugin works to allow authors to create categories. Is there a way to prevent an author from posting in changing a category he or she did not create?
I think that would be the Limit Categories Plugin. Same author as the first. He’s been recovering from a site crash, so not sure if that one’s up yet or not.
Maybe google around for it?
I was hoping for something that would do this more automatically. I’ve only been able to read about Limit Catagories, I can’t find the file, but from what I have read. It looks like I’d need to manage the categories that were limited to specific users.