What is CPanel?
CPanel is a fully featured web-based control panel that allows you to manage your domain through a web interface. The idea is to transfer as much of the control and responsibility of managing your web site to you. You have the ability to manage all aspects of e-mail, files, backup, FTP, CGI scripts, and web site statistics.
Refer to How do I use CPanel? for more information on how to CPanel's features.