Improved to let your Mac run Windows applications more productively. Virtual PC supports both Mac OS X and Mac OS 9, so it's flexible enough to cater to every user. Virtual PC makes it easy to run Windows programs, access PC networks, use Windows-only Internet applications and share files with PC-based colleagues. With Version 6.1, those running the latest version of Jaguar will find an overall speed improvement of up to 25%. Users will experience a new Dock integration which delivers the ability to launch Windows applications directly from your Mac OS X Dock! Other new features include desktop mounting of drive images*, increased video RAM and automatic detection of USB printers.
http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/71402/wo/xppqcxUPXu2e3TCeQEN1CkTDbR2/2.4.0.5.10.11.6.13.0