ControlPanels: Top OpenSource CPanel Alternatives in Linux

cPanel is a Unix based web hosting control panel that provides a graphical interface and automation tools designed to simplify the process of hosting a web site its also the one of popular hosting control panel to date but unfortunately its not free.
 Top OpenSource CPanel Alternative in Linux
1. Kloxo 

Kloxo allows the host administrators to run a combination of lighttpd or Apache with djbdns or BIND, and provides a graphical interface to switch between these programs without losing data. Kloxo Enterprise can transparently move web/mail/dns from one server running Apache to another running lighttpd. It is also known as a good free alternative to cPanel hosting control panel.
Kloxo comes integrated with Installapp, which is a bundle of approximately 130 web applications that can be installed to the hosted websites. It is supported by Installatron - a third party application installer (similar to Fantastico) as a plugin.
 2. Webmin 

 Use it for a while everything was working good just i did not like the template much . Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely
3.ISPConfig 

ISPConfig is an open source hosting control panel for Linux, licensed under BSD license and developed by the company ISPConfig UG. The ISPConfig project was started in autumn 2005 by the German company projektfarm GmbH.

4. Ajenti 

Ajenti is a simple, fast and small web based administration tool for managing your servers. It is similar to Webmin. It is very useful for those who are not that much good at command line interface. It is available for almost all distributions such as Debian, Ubuntu, CentOS, Arch, Gentoo and FreeBSD etc. Using this tool you can check CPU resource usages, DNS, firewall configuration, manage cron jobs, backup/recovery settings and more. All you need to do is install the relevant plug-ins and start managing your servers.
5. Ehcp 

Ehcp is a Free Hosting Control Panel for Ubuntu/Debian/Mint/Pardus and similars, a web based software for managing your hosting server. You can manage your domains, ftp, emails and more using EHCP 
6. Zpanel 

Zpanel - Web hosting control panel written to work effortlessly with Microsoft Windows an POSIX (Linux, UNIX and MacOSX) based servers or computers.
This solution can turn a home or professional server into a fully fledged, easy to use and manage web hosting server.

Good Luck For You!!