VirtualBox 2.2.0 is here.
Download from these url links and try it out.
http://www.virtualbox.org/wiki/Downloads
or
http://dlc.sun.com/virtualbox/vboxdownload.html
More Information:
http://www.virtualbox.org/
http://www.sun.com/software/products/virtualbox/index.jsp
VirtualBox have come a long way and now it has more improvement.
I personal use it on my MacPro, MacBook Pro and Sun Ultra 40.
I use for Solaris, OpenSolaris and other guest operating systems.
And VirtualBox works for me. 
I am loving it.