Re: skype on 64 bit
You have enable "Cannonical Partners" and "Independent" repositories to be able to install Skype and a lot other applications from Ubuntu Software Center or Synaptic Package Manager. These repositories are not enabled by default. I would recommend that you install and use Synaptic; you can install it from Software Center or the Terminal.
To install Synaptic from Terminal:
After installing and opening Synaptic navigate to Settings -> Repositories and select "Canonical Partners" and "Independent". After that you have to "Reload" from Synaptic. Then search for Skype and Install it.
$ sudo apt-get update
$ sudo apt-get install synaptic
Skype is not available as 64bit for Linux, so we have to install 32bit with the required libraries and dependencies to run it in a 64bit Linux. Synaptic Package Manager will take care of all that for you.
"Evolution is Nature's way of issuing upgrades."