[Cube] Offtopic: Software for writing manuals/documentation?

[Riba]

I know I am abusing the list, but this is the only list I'm subscribed 
to and I've always gotten some great help here. :)

I'm looking for a software specialized for writing manuals. It sounds 
weird, but a friend has something like that on Windows - it allows you 
to write chapters, maintain different versions, and it will 
automatically compile a nice manual using different file formats or 
layouts. I'm hoping that there is something similar for Mac, or at 
least a suggestion how to effectively do it using the 'generic' tools. 
Please mail me not to pollute the list. Thanks!