VMware on Wednesday released Fusion 4, the company’s virtualization software, allowing users to run other operating systems on their Macs.

Fusion 4 is a 64-bit Cocoa application, built with Apple’s new OS X Lion in mind. You can add Windows applications to LaunchPad, experience them in Mission Control, view them in full screen or switch between them using Mac gestures.

VMware said Fusion is also optimized for today’s multi-core Macs and delivers 3D graphics up to 2.5-times faster than previous versions.

Fusion 4 now supports OS X Lion in a virtual machine, so you can run OS X Lion, OS X Lion Server, Mac OS X Snow Leopard Server and Mac OS X Leopard Server in virtual machines.

Pat Lee, director of client product management at VMware, pointed out in an interview with The Loop that having the ability to run OS X in Fusion is a great way to test Mac apps, or different setups, without affecting your working machine.

“A big part of Fusion users are switchers that want to run the apps that they still need,” said Lee. “We want to make that easy.”

VMware Fusion 4 is available until the end of the year for $49.99. Customers who have purchased Fusion 3 on or after the July 20, 2011 are eligible for an electronic upgrade to Fusion 4 at no additional cost.

Fusion will not be available from the Mac App Store, but can be purchased from VMware.