Mark

Adds a simple ‘Post-it’ widget to the Dashboard that allows you to leave yourself or other authors a note. The plugin can be configured and moved around as any other Dashboard widget. It will accept plain text or (sanitized) HTML. Only users with the capability “Edit dashboard” can edit the note.
This simple plugin is based on code from <a href="http://wpengineer.com/add-wordpress-dashboard-widgets/" title="Add WordPress Dashboard widgets" rel="nofollow ugc">WP Engineer</a> and <a href="http://rick.jinlabs.com/2009/02/01/how-add-options-to-your-wordpress-27-dashboard-widgets/" title="How to add options to your WordPress 2.7 Dashboard widgets" rel="nofollow ugc">Ricardo González Castro</a>. Leave your comments <a href="http://ideophone.org/dashboard-post-it/" title="Dashboard Post-it homepage" rel="nofollow ugc">here</a>.
Warning Your notes will be replaced by boilerplate text upon upgrading. Make sure to copy the content somewhere else before you upgrade and then paste it into the new version. Sorry about that!

Dashboard Post-it

Adds a simple 'Post-it' widget to the Dashboard that allows you to leave yourself or other authors a note.

Galaxy Weblinks

The QuickNotes Dashboard plugin integrates a customizable note-taking feature directly into the WordPress dashboard. You can create QuickNotes with various settings, such as:
<ul>
<li>QuickNotes Context: Position the note in the normal area or the side panel of the dashboard.</li>
<li>QuickNotes Priority: Set the note’s priority to either High or Low.</li>
<li>QuickNotes Target: Specify which user roles or individual users can view the note.</li>
</ul>

QuickNotes Dashboard

This plugin adds the functionality to add QuickNotes to the WordPress dashboard.

Dashboard Post-it vs QuickNotes Dashboard