VirtualBox for Linux Download

BleepingComputer Review:

VirtualBox is an enterprise-ready virtual machine tool which allows you to run any operating system with full-functionality as a window on your desktop. It's possible to run any guest operating system which your computer can use as a host operating system. It is available in one edition; The standard edition is licensed under the GNU GPL which means that anyone can use it for any purpose free of charge as long as they abide by the GPL. Extensions exist which are not open source and therefore are distributed separatly from the standard download and are for personal use only. 

The extensions can be found here: On the VirtualBox Download Page

Company's Description:

VirtualBox is a general-purpose full virtualizer for x86 hardware, targeted at server, desktop and embedded use.