See the Microsoft VPC page for details. It's just in time to use with a new iMac G5! Some of the highlights of the release include:

• G5 support (duh!)
• Ships with Windows XP SP2
• Some nice performance improvements, including making better use of the GPU
• Zero configuration printing (if using Panther) - setting up printers used to be a major pain. Now, it's seamless, thanks to help from Panther's Postscript to PDF functionality
• Refined UI - the preference and other UI has been refined to be easier to use
• Usability improvements - various improvements were made in the setup and basic usage based on usability testing