Oracle has released VirtualBox 4.0.8, this is a maintenance release of VirtualBox 4.0. It improves stability and fixes regressions. VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers, it is also the only professional solution that is freely available as Open Source Software under the terms of the GNU General Public License (GPL) version 2.
To install VirtualBox open a terminal window (press Alt+F2 and type: gnome-terminal) and copy+paste the following lines:
echo “deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -sc) contrib” | sudo tee /etc/apt/sources.list.d/virtualbox.list
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
sudo apt-get update
sudo apt-get install virtualbox-4.0
For some additional features like USB 2.0 support, you’ll have to install the VirtualBox Extension Pack which you can download here. Once downloaded, double click the Extension Pack and it should open with VirtualBox and you can then easily install it. If that doesn’t work for you, Open VirtualBox and go to File > Preferences and on the Extensions tab, click the “add” button on the right and browse for the VirtualBox extension pack.
To install the guest additions on Ubuntu 11.04 “Natty Narwhal” copy+paste the following line:
sudo apt-get install virtualbox-ose-guest-utils