What are the options to install Skype in Ubuntu 11.04?
If you enable (this link tells you how) the partner repository within your software sources (and reload the list).
Now you should be able to install Skype in 11.04 from the Software Centre.
Screenshot, it happened.
Have you tried the packages for Ubuntu 10.04 or more that are available on the Skype Linux download page ? I would think they will also work on 11.04. And make sure to use the right package for your Ubuntu version, either 32 bits or 64 bits.
To get Skype just go to the Ubuntu Software Center and search for "skype", then it will return the Skype software, select it and click on the Install button, it's supposed to install the latest Skype client for Linux. To start Skype just search for it in the Unity Dash or if you're using Classic Gnome go to Applications > Internet > Skype.
The easiest way, in 12.04, download the .deb file from www.skype.com/intl/es/get-skype/ , and simply open it. It should open your Ubuntu software center. So it will check if you have already installed it in your computer, in this case it will offer you to upgrade or install it directly from the Software Center window !