genkisan

<ul>
<li>easily switch on and off through Admin Options</li>
<li>display message without editing theme files (above 1st post or through widget)</li>
<li>display different message to different roles/users</li>
</ul>
Demo: 
<a href="http://ericulous.com/2007/03/09/genki_announcement/" rel="nofollow ugc">Plugin Details & Demo</a>

Genki Announcement

Amber Hinds

Steve Jones

Road Warrior Creative

Sometimes you simply want to allow users with the defined user role of “contributor” to upload images as they are writing blog posts. This plugin, when activated, automatically gives contributors the capability to add media. This is a lite plugin, perfect for someone who only wants to modify this one role/capability in which case a larger roles and capabilities plugin would be overkill.

Enable Contributor Uploads

Easy plugin which adds the capability for contributors to upload images to their blog posts.

Genki Announcement vs Enable Contributor Uploads