This plugin is not available anymore!
New features in WordPress 3.0+ as custom post types and post formats introduced some challenges to webmasters of corporate websites with many users holding post publishing / editing privileges. Especially post formats which use the standard post editing screens but may have certain rules imposed by the implementation. Click on a link above this post to see the plugin in WordPress repository.
Webmasters could try the following options: make a course / training for editors, distribute instructions for editors in a form of printed material, or give editors a link to the documentation. All these methods are good based on one assumption that editors will remember where to find this information. Unfortunately information obtained during the course can be forgotten, printed materials lost or misplaced, and, as everybody knows, people tend to avoid reading documentation.
In attempt to solve this set of problems I have developed FPW Post Instructions plugin. The plugin adds a metabox to post editing screens with special instructions for editors. You can make it as eye-catching as you want ( html in the content is allowed ). It will show on every post editing screen so it cannot be forgotten or misplaced.