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 two editions: standard and OSE. The OSE 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. The standard edition incorporates extra features which are not available in the OSE edition such as support for USB devices. It is free for personal use and evaluation purposes.

Installers are available for Windows, Mac OS X, and Linux (Debian, RPM, urpmi, and as a binary installer.) You must download the correct bit-width for your computer

Product Description from Oracle Corporation:

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