How to install Skype from repository in Ubuntu 9.10

Skype is not available in any Ubuntu software repository, and therefore cannot be installed with Ubuntu's package management software such as Synaptic or apt-get without adding a repository containing Skype. There is an official Skype repository.

How to install Skype from the official Skype repository

1. Add the official Skype repository by running the following command in the Terminal (Applications -> Accessories -> Terminal):
   

   echo "deb http://download.skype.com/linux/repos/debian/ stable non-free #Skype" | sudo tee -a /etc/apt/sources.list > /dev/null

2. Import the Apt key, even it is not used, but may be useful in future:
   

   gpg --keyserver pgp.mit.edu --recv-keys 0xd66b746e && gpg --export --armor 0xd66b746e  | sudo apt-key add -

3. Then download and install skype by running
   

   sudo apt-get update && sudo apt-get install skype

   Confirm installation by pressing "Y" and then "Enter".
   
   Ignore the warning about an untrusted package by typing "Yes" and then "Enter".

Using a repository, you will automatically receive future updates to the software. Please be aware that the repository is not signed, so when you try to install Skype, you will get a warning.

If you don't want to do that, or can't (for example, if you're on amd64), perhaps the easiest way to install is from the Debian (.deb) package available directly from the Skype website. The downside of this is that you won't automatically get future updates, you will have to download the new versions as they become available.