cPanel:

cPanel (control panel) is a graphical website management tool. The software, which is proprietary, runs on most widely used Linux distributions, and FreeBSD. It is designed for use by commercial web hosting services, so the company does not offer a reduced-cost personal use license. cPanel gives you more control to access and manage your web site. You have the ability to manage all aspects of e-mail, files, FTP, CGI scripts, and web site statistics. The cPanel software is distributed by Darkorb Communications Inc., doing business as cPanel Inc.

WHM (Web Host Manager):

WHM is a graphical tool used to manage all of the websites hosted in a web server. It is a web-based tool used by server administrators and resellers to manage hosting accounts on a web server. It is usually used in conjunction with cPanel, a tool used by clients to manage their account. WHM listens to port 2086 by default. The most common WHM is cPanel.

Fantastico:

Fantastico is an amazing cPanel/PHP based Web application. cPanel Fantastico is the leading autoinstaller for cPanel Dedicated Servers. It integrates with your cPanel Dedicated Servers
and gives you and your web-hosting customers the ability to install multiple instances (*) of any of these scripts:
- in add-on domains and in sub domains
- in top level directories (root of main domain and/or any add-on domain/sub domain)
- translate the English language file and give your clients auto-installation in their own language
- create Features Sets so different users have different set of available scripts
- get notifications when users install/remove applications
- have a complete overview over the installations performed by your users
- Display a warning when logged in using root or reseller password. You can’t proceed to install in these cases.

cPanel Flash Tutorials