Skype is a very popular software that allows you to make free calls over the Internet and talk with friends,family face to face. This tutorial shows how to install the latest stable version in Ubuntu from Skype repository which will automatically keep the software update to date.

Open terminal from Applications->Accessories menu and type this to edit /etc/apt/sources.list:

gksudo gedit /etc/apt/sources.list

add the following line and save the file.

deb stable non-free

Add the gpg key and update your system:

sudo apt-key adv --keyserver --recv-keys 0xd66b746e
sudo aptitude update

Now,install Skype and you can launch from Applications->Internet menu.

sudo aptitude install skype

NOTE:I have tested in amd64 system,but unfortunately this only works in i386 system.
And for amd64 users,use following commands to download current 64-bit version from skype website:

wget -O skype_ubuntu-current_amd64.deb
sudo dpkg -i skype-ubuntu-current_amd64.deb
sudo rm skype-ubuntu-current_amd64.deb

and you might still need to install the needed packages first:

sudo apt-get install ia32-libs lib32asound2 libqt4-core libqt4-gui