While some open-source projects formerly under the control of Sun Microsystems have been mistreated since being acquired by Oracle (i.e. OpenSolaris 2010.03 still is M.I.A.
with little communication from Oracle employees), VirtualBox continues to improve. Just last week VirtualBox 3.2 Beta 1
was put out and now the second beta has arrived with more features.
VirtualBox 3.2 Beta 1 brought experimental support for Mac OS X guests, memory ballooning, CPU hot-plugging, new hypervisor features, RDP video acceleration, and much more. With VirtualBox 3.2 Beta 2, Oracle has introduced Java bindings for VirtualBox, numerous GUI enhancements, fixes for Ubuntu 10.04 LTS guests, new icons, performance optimizations, and various other fixes.
The VirtualBox 3.2 Beta 2 release details and download links can be found within the VirtualBox Forums