Parallels Workstation 2.1 Beta for Mac OS X creates a virtual machine on an Intel-based Mac, allowing the owner to install any guest OS compiled for X86, including Windows XP, Linux or MS-DOS. This could allow Mac users who need to run an occasional Windows app to do so without having to reboot first -- though they'll need enough RAM and processing power to run both OS X and the virtual machine simultaneously. While other apps, including Microsoft's Virtual PC, have offered similar functionality for Power PC Macs, they required processor emulation, seriously undermining performance. By contrast, Parallels Workstation (available as a free beta) is said to provide "near native" performance, which might be enough for users who need to run Visio, Project, or one of the many other Windows-only productivity apps -- though gamers will probably still want to use Boot Camp and keep just one OS running at a time.