WPAlerts is a free plugin that helps you to make updates on your WordPress sites (with the WPAlerts software http://wp-alerts.com/).
Authors Widget shows the list or cloud of the authors in the sidemenu.
Easily reorder your admin menu items with simple drag & drop operation
This plugin displays the latest posts by the currently logged-in user in a dashboard widget.
version: 1.0 Easily remove any/all of the default WordPress dashboard widgets for specific user role. Useful for multi-user blog.
Multi-user aware Twitter plugin adds a tweet button to posts and/or automatically tweets bit.ly or su.pr links to new posts.
Flickr PhotoStream displays Authors photostreams links as a sidebar widget. If Shadowbox plugin installed, the photostream Lightbox will appear.
Allows authors to add a picture to their profile and automates the process of displaying profiles. Highly configurable via plugin and widget settings.
WP-Universe creates a blog universe based on categories of a WordPress blog.