From LinuxDevCenter.com

Although you don’t need to go far to hear someone extolling the benefits of Linux and free software, many people still need to use other operating systems, such as Microsoft Windows and Apple Mac OS X. Aside from personal choice, other reasons to use non-Linux operating systems include running applications that are available only on a particular OS, an employer mandating that you use a particular platform, or even a need to test software and services across different platforms. For some, the solution is a huge desk set up to accommodate three computers with three monitors and three keyboards/mice; however, there is a better way.