This plugin is the easiest way to implement announcements I could think of. I tried out several others and wrote one myself instead.
Change the announcement in the Options panel.
Unzip or untar the files and place the wp-easier-announcements folder and place it in you wp-content/plugins folder.
In your Header file, insert (without the quotes) ‘eea()’ at the very bottom.
Activate it in the Plugins admin panel.
Contributors & Developers
“Even Easier Announcements Plug-in” is open source software. The following people have contributed to this plugin.