How to upgrade VirtualBox to the latest version?
Head on over to this page and download the Ubuntu package for your version / architecture.
Be sure to get the VirtualBox extension pack too. (This provides USB 2.0 and RDP support.) The most recent version can be found on the VirtualBox Downloads page.
Add one line to your /etc/apt/sources.list:
deb http://download.virtualbox.org/virtualbox/debian maverick contrib
The Oracle public key for apt-secure can be downloaded here. You can add this key with
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
To install VirtualBox, do
sudo apt-get update
sudo apt-get install virtualbox-4.0
You should be able to upgrade virtualbox from the ppa available from virtualbox directly.
There is also a good ppa if you want to make sure you keep the open source edition (ose):
https://launchpad.net/~debfx/+archive/virtualbox