In this tutorial we will learn , how to install Virtual Box in Ubuntu 14.04 LTS (Trusty Tahr).
VirtualBox is free Virtualisation Sofware under the GNU General Public License Version 2.
Presently, VirtualBox can be installed on Windows,Linux,Macintosh and Solaris.
It is one of the popular Virtualisation Software among System Admins. It is one of the alternate of properietry VMWare (Desktop version) . With VirtualBox you can do most of the practicals,it is free and team do timely update , that is the reason it is popular among many System Admins.

Recently, the latest stable VirtualBox release is version 4.3.10 .Its release was announced on 25 March 2014 . On other hand, recently Ubuntu 14.04 LTS is also released. Both VirtualBox and Ubuntu version have announced stable releases in recent times. Hence, I decided to quickly taste these both flavours.

Install VirtualBox in Ubuntu 14.04 LTS (Trusty Tahr)

Follow the given below steps to install the VirtualBox version 4.3.10 on Ubuntu 14.04 LTS (Desktop) .

Step 1: Add VirtualBox repo link in apt source list . We will edit /etc/apt/sources.list file.

sudo vim /etc/apt/sources.list

Now paste below given lines at the end of file /etc/apt/sources.list . And save the file.

deb http://download.virtualbox.org/virtualbox/debian trusty contrib

Step 2 : Download and add Oracle public key for apt-secure.

wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -

Step 3 : Install DKMS package

sudo apt-get install dkms

Step 4 : Now install VirtualBox 4.3.10

sudo apt-get update
sudo apt-get install virtualbox-4.3

Step 5 : Now after installation, you can open the VirtualBox from Dashhome .
To know about VirtualBox version click on Help >> About VirtualBox .
Or you can also use sudo dpkg -l|grep VirtualBox command

The below given reference is from my laptop.

sharad@linuxworld:~$ sudo dpkg -l|grep VirtualBox
ii  unity-scope-virtualbox                                0.1+13.10.20130723-0ubuntu1                         all          VirtualBox scope for Unity
ii  virtualbox-4.3                                        4.3.10-93012~Ubuntu~raring                          amd64        Oracle VM VirtualBox
sharad@linuxworld:~$

Now you can start creating new virtual machines in VirtualBox.