snydeq writes: InfoWorld's Randall Kennedy takes an in-depth look at VMware Workstation 7, VirtualBox 3.1, and Parallels Desktop 4, three technologies at the heart of 'the biggest shake-up for desktop virtualization in years.' The shake-up, which sees Microsoft's once promising Virtual PC off in the Windows 7 XP Mode weeds, has put VirtualBox — among the best free open source software available for Windows — out front as a general-purpose VM, filling the void left by VMware's move to make Workstation more appealing to developers and admins. Meanwhile, Parallels finally offers a Desktop for Windows on par with its Mac product, as well as Workstation 4 Extreme, which delivers near native performance for graphics, disk, and network I/O. 'There's some genuine innovation going on, especially in the areas of hardware support and application compatibility,' Kennedy writes. 'All support 32- and 64-bit Windows and Linux hosts and guests, and all have added compelling new VM management capabilities, ranging from automated snapshots to live VM migration.'