Macromedia releases RoboHelp X5, the first product for help systems.
This sounds interesting:
Import any existing documentation, whether it's in HTML, Microsoft Word, Adobe FrameMaker, PDF, or XML.
Also this:
Create and edit content in your choice of editors, including any popular HTML editor such as Dreamweaver, RoboHelp's built-in HTML editor, or Microsoft Word.

But the price 999 US Dollars is pretty high...