Official StatementParallels Desktop 7 for Mac is compatible with Mac OS X Lion. When using Parallels Desktop with Mac OS X Lion, you can also run Lion as a guest operating system in a virtual machine.
Note: When using Parallels Desktop with previous versions of Mac OS X, such as Mac OS X Snow Leopard, Lion cannot be used as a guest OS.
Parallels Desktop 7 takes advantages of new Mac OS X Lion features including:
• Application resume
• Full-screen apps
• Animation support for Windows installed in a virtual machine
Refer to this article to learn how to install Mac OS X Lion in a Parallels Desktop 7 virtual machine.