A set of custom tweaks to the WordPress Admin Bar that was introduced in WP 3.1. Since version 3.3.5 of this plugin, it is only compatible with WP 3.3
Use the built in WordPress Plugin Installer via Plugins -> Add New, searching for "WordPress Admin Bar Improved"
Extract all files from the ZIP file, making sure to keep the file structure intact, and then upload the plugin's folder to
/wp-content/plugins/ via FTP.
This should result in the following file structure:
- wp-content - plugins - wordpress-admin-bar-improved | readme.txt | screenshot-1.png | wpab-admin.css | wpabi-admin.js | wpabi.css | wpabi.js | wpabi.php
Then just visit your admin area and activate the plugin on the Plugins screen.