Parallels is one of the few virtualization softwares available for Mac which includes VirtualBox and VMWare Fusion. VMWare Fusion was the only one that allowed OS X Lion installs, until now. Parallels just released an update to their Parallels Desktop 7 allowing support for OS X Lion installations as well a Windows 8 installations.
While there are other fixes and improvements, the ability to download and install Windows 8 Developer Preview from within Parallels is a great perk. Along with that is the ability to install OS X Lion using the file downloaded from the App Store, support for Ubuntu 11.10, improved full screen experience, and improved migration of Linux versions from PC to virtual machine.