Fedora Core 5 Linux has been released and includes, among other things, integrated virtualization. 

FC5 can now run multiple operating systems using Xen's virtualization application.  Using this feature, users are able to create virtual machines running guest operating systems much like VMware products and Microsoft virtualization platforms.  Unfortunately for many, it does not yet officially support running the Windows operating system as a guest OS.  It also does not yet support running FreeBSD. 

Congrats to those working on the project for your announced release!