The xVM Server Project is a data-center grade, bare-metal
virtualization engine that provides hypervisor lifecycle management for
servers. It is designed to be a cross-platform, high efficiency, open
source hypervisor capable of hosting multiple guest operating systems
(including Solaris, Windows, and Linux), with advanced CPU and memory
handling capabilities. The server is being built using technology from
the Xen open source project as well as Sun™ Logical Domains (LDOMS).

Keep your browsers tuned to xvmserver.org, the site is set to launch this summer. For now you can check out a UI sneak peak and a short overview of xVM Server over at the OpenxVM.org’s OpenxVM at a Glance page.

Version 1.6 (Download) has new Mac and Solaris host platform support, support for seamless windowing for Linux and Solaris guests, new high performance virtual devices, improved scalability and Web Services API, SATA hard disk (AHCI) controller, and Experimental Physical Address Extension (PAE) support was also introduced.

Check out the VirtualBox Changelog to see the full list of updates.