If I look in the Ubuntu Software Center and search for Skype I see two choices. If I select one and then click More Info it tells me that the package is available from the oneric-partner repository. If I attempt to install the package I am told that it is not found in any of my current software sources. Well, here is the rest of the story...
I am using a test install of 11.10 as a virtual machine under VMWare.
The Partners repository is not selected by default
The Software Center added the Partners repository but did NOT download a current list of packages.
sudo apt-get update forced the package list to be updated and now I can install the Skype package.
Make sure Canonical Partners is checked in Software Sources (it is on the Other Software tab).
Refresh the package list. I have no idea how to do this within the Software Sources GUI (typical of the morons at Canonical - Synaptic had a button to do this and even reminded you to do it after changing repository selection - Canonical decided to make it easier to use by removing the ability to do this necessary step - way to go). And stepping down from my soap box I open a terminal and use the command I stated above
and you should be able to install the Skype package.
p.s. I see for the other response that there are some issues running Skype on 11.10. I don't use Skype so I cannot confirm if the current package will work. I was simply trying to answer the "how to install" question.