What exactly do you need assistance on? Do you mean how to frame the content? How to create the on-line help?
In general, as was already mentioned, RoboHelp and DocToHelp are really good tools for this - although vastly more expensive than you might necessarily need depending upon how you want to create the help.
For a more sophisticated Web-based tutorials or online help complete with audio and video support, you may want to check out the Macromedia Authorware product.
more info at www.macromedia.com
otherwise, go with RoboHelp.
For advice, know your audience and keep your online help as simple as possible. Make sure you cover the different screen resolutions you'd like to support and pick the appropriate fonts to use. If you need to add a lot of pictures/bitmaps, double check the way they get displayed on the screen.
[This message has been edited by Gilbert (edited 10-04-2001).]