Designing Help Text
http://infocentre.frontend.com/infocentre/articles/designinghelptext.html

Farrell, Tom
Frontend Infocentre
2001

Abstract:

In an ideal world help text would be unnecessary - users would never get stuck in an application or site. It should be enough to provide clear design, carefully chosen titles and labels for the various functions, appropriate field prompts when user entry is required, helpful feedback, a glossary, and 'embedded' help such as default values, example input, on-screen step-by-step instructions and explanatory text next to fields or functions. Help features should certainly be a last resort. Anyone embarking on adding it to an application or site should be sure that they have already followed the best practise listed above. In most cases (certainly online) a help option should not be necessary.