How do I put this gently... No. No, its not.
Xen is indeed a neat technology. For those of you who arent familiar with it, Xen is a virtual machine monitor for x86. In English, what that means is that with Xen, and a PC with enough processor horsepower and RAM, you can run several operating systems at once.
Older, commercial VM (virtual machine) programs like VMWare support multiple operating systems like Windows, Linux, and Solaris.
Xen, however, which just reached version 3.0, only fully supports the Linux 2.4 and 2.6 kernels.
Xen will soon be offering support for FreeBSD and NetBSD, but if you want to run Windows and Linux today on the same PC, youre better off with VMWare or Win4Lin.
Now, even just supporting Linux virtual machines is still useful. After all, Xen 3.0 does support up to 32 processors and more than 4GB of memory in 32-bit computing environments. With that you can certainly run enough Apache Web servers or Samba file servers to keep a medium sized business happy.
Another difference, though, between a VMWare and Xen, is that for Xen to really do its stuff, it needs to be running on a Linux distribution thats been designed to properly support it. Fortunately, Xen has been really hot in Linux circles and both Red Hat and Novel/SUSE come with Xen-enabled kernels.