If you have a previous version already installed you need to manually install the new one.
- Go to System > Administration > Software Sources and Third-Party Software.
- Add the following sources for Intrepid (check your distribution here)
- Download and register Sun authentication key
$ wget -q http://download.virtualbox.org/virtualbox/debian/sun_vbox.asc -O- | sudo apt-key add -
- Be sure your source list is updated
$ sudo apt-get update
- Be sure you have dkms installed (so Virtualbox host kernel is automatically updated as you update your system kernel)
$ sudo apt-get install dkms
- Install Virtualbox 3.0
$ sudo apt-get install virtualbox-3.0
- Logoff and login again
- Start Virtualbox at Applications > System Tools > Sun xVM VirtualBox
- If you want you can optionally register your VirtualBox installation
- If you have a Windows Virtual Machine don't forget to install the Guest Additions (after starting the virtual machine go to Devices > Install Guest Additions).