Sun Microsystems has released the version 3.1.0 of its open source VirtualBox desktop virtualisation application for x86 hardware. VirtualBox 3.1.0 is a major update that, in addition to the usual bug fixes and changes, adds a number of new features.

From changelog, the new features are:

• Teleportation (aka live migration); migrate a live VM session from one host to another.
• VM states can now be restored from arbitrary snapshots instead of only the last one, and new snapshots can be taken from other snapshots as well ("branched snapshots")
• 2D video acceleration for Windows guests; use the host video hardware for overlay stretching and color conversion.
• More flexible storage attachments: CD/DVD drives can be attached to an arbitrary IDE controller, and there can be more than one such drive.
• The network attachment type can be changed while a VM is runnin.
• Complete rewrite of experimental USB support for OpenSolaris hosts making use of the latest USB enhancements in Solaris Nevada 124 and higher
• Significant performance improvements for PAE and AMD64 guests (VT-x and AMD-V only; normal (non-nested) paging).
• Experimental support for EFI (Extensible Firmware Interface).
• Support for paravirtualized network adapters (virtio-net).

You can get a copy from here.