We have recently become a cPanel partner and we can now install cPanel and Web Host Manager on any of our Linux Dedicated Servers for just £20 per month. This includes us installing the software and an unlimited domain license.
Web Host Manager allows just about anyone to manage a server, it takes care of all the server side configuration and services. cPanel allows you or your customers to manage their website including mail, logs, stats, security, databases and more.
A few useful links to help you find out more:
Linux Dual Core Dedicated with cPanel
cPanel & WHM Product Information