After conquering the desktop virtualisation space on the Mac, Parallels has decided to take the fight to VMware with a client for Windows and Linux desktops. But unlike the bi-polar world of the Mac (with Parallels and VMware being the only options), Parallels faces a multi-pronged attack on Linux, from proprietary brethren like VMware’s Workstation, and free-to-download options such as Sun’s VirtualBox.