cPanel's WebHost Manager, or WHM, is an easy to use Web application that provides administrative control of your dedicated or Virtual Private Server (VPS). You use WebHost Manager to create individual accounts, add domains to your server, manage hosting features, and performing basic system and control panel maintenance.
WebHost Manager is used in conjunction with cPanel. cPanel is designed for managing particular domains or hosting accounts on your dedicated or Virtual Private Server (VPS). End users can control everything from adding/removing email accounts to administering MySQL databases.
For more information about cPanel and WebHost Manager, visit the cPanel website at http://www.cpanel.net.