If you have used any of my libraries you will have seen the help files I make with HelpMaker http://www.vizacc.com/
It is unintuitive with a strange user interface, does odd things on occasion and always ends its' compilation with an error! However it does produce usable help files, is free and is the solution that I settled on after trying several others. They mostly had a much more complicated production process that separated the text preparation from the help file compilation. With HelpMaker you just type your content then press F9 to compile and view the resulting help file.