WordPress.org

1. Upload the 'widgetizeddashboard.php' file to the '/wp-content/plugins/' directory
2. Activate it
3. Go to Design > Widgets and choose the "WordPress Dashboard" sidebar option from the drop down
4. Add widgets to your heart's content!

Note: When you select "WordPress Dashboard" 4 new widgets will show up at the bottom of the widget list, all starting with "Dashboard: "

3 are the same admin widgets that come with WP - Recent Comments, Incoming Links, and Plugins.

The fourth, RSS, is a modified version of the sidebar RSS widget - it does the same thing, but includes some new options, like height, width, and a drop down that includes some popular RSS feeds from blogs about WordPress.