VirtualBox 2.0.0 is out!

开源虚拟机，其强大性不用多说，尤其是在被Sun收购之后也更日趋强大

This version is a major update. The following major new features were added:

64 bits guest support (64 bits host only)
New native Leopard user interface on Mac OS X hosts
The GUI was converted from Qt3 to Qt4 with many visual improvements
New-version notifier
Guest property information interface
Host Interface Networking on Mac OS X hosts
New Host Interface Networking on Solaris hosts
Support for Nested Paging on modern AMD CPUs (major performance gain)
Framework for collecting performance and resource usage data (metrics)
Added SATA asynchronous IO (NCQ: Native Command Queuing) when accessing raw disks/partitions (major performance gain)
Clipboard integration for OS/2 Guests
Created separate SDK component featuring a new Python programming interface on Linux and Solaris hosts
Support for VHD disk images

In addition, the following items were fixed and/or added:

VMM: VT-x fixes
AHCI/SATA: improved performance
GUI: keyboard fixes
Linux installer: properly uninstall the package even if unregistering the DKMS module fails
Linux additions: the guest screen resolution is properly restored
Network: added support for jumbo frames (> 1536 bytes)
Shared Folders: fixed guest crash with Windows Media Player 11
Mac OS X: Ctrl+Left mouse click doesn’t simulate a right mouse click in the guest anymore. Use Hostkey+Left for a right mouse click emulation. (bug #1766)

for more： http://virtualbox.org/wiki/Changelog