There are several good tools for creating help files. Two I know of are called Doc-to-help and Robohelp. I think Doc-to-help is a good choice if you want a single tool to manage your printed documentation and your help files. I would use Robohelp if you're looking for a tool just for help files.
You should be able to find these products on the web. Any major software distributor will probably carry them.
>who is the best way to create a good help file?