Upgraded my system yesterday to 11.10, and Skype stopped working. Downloaded all kind of binaries and packages from Skype and nothing worked. After a few hours I found the instructions on the Ubuntu Oeneric page to install Skype like this and it works again.
First add the partner repostiory
sudo add-apt-repository "deb http://archive.canonical.com/ $(lsb_release -sc) partner"
Then install skype
sudo apt-get update && sudo apt-get install skype