cPanel is the most popular Control Panel tool on the web hosting market. It's feature-rich and has an easy-to-use interface which will provide you with full control over your web sites. You can easily manage files, email addresses and databases, take a look at usage statistics, install script-driven applications, and the like. This software is preferred by many website hosting companies, since it also has a reseller counterpart named WebHost Manager (WHM). This tool will provide you with a web-based graphical interface, via which you're able to manage a number of server-side settings, set up web hosting plans or new client accounts and modify their features with just a few clicks. You may also set up different modules and applications, customize DNS records, brand all the cPanel accounts that your clients will get, create and remove features from their Control Panels, etc. cPanel and WHM are supported by almost all billing applications out there, so this is one of the best platforms if you wish to become a reseller.