As a WordPress theme/plugin developer I came across the need to add notifications and communicate additional information to the user. To this end I have developed wp-admin-notificaitions - a free PHP script that helps you add these notifications with a single line of code. The script also handles the dismissal of the notifications, ensuring that dismissed notifications will not be shown again. For an in-depth tutorial, see my tutorial about Adding Static/Dismissible Admin Notifications to WordPress.
Hope you guys find this useful!