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Parallels Desktop for Mac is a software product by Parallels, Inc., a developer of desktop and server virtualization software. Released on June 15, 2006, it was the first software suite to bring hardware virtualization mainstream to Macintosh computers with Intel processors.
On January 10, 2007, Parallels Desktop 3.0 for Mac was awarded "Best in Show" at MacWorld 2007.
Download the demo here.
Advantages: Allows users to quickly switch between OSX and Windows.
Disadvantages: Using Windows Vista's Boot Camp partition results in needing to reactivate Windows.