Go to http://www.skype.com/intl/en-us/home and click on get skype.
You should be able to find the version for your popular distro. If not they have generic install but that is a bit more involved to install. You will need to know what version (32 bit for most older systems and 64 bit for the latest systems). I chose 32 bit Fedora for Fedora 16.
Click on the version for your system. Then you should be presented with a window for whether to save or just install the software. I like to save the software for later so I do not have to re-dowload it. We will just install the software.
You will be asked to read their eula (end user license agree). Read it carefully!! If you agree then go on with the install.
You will probably be asked for the root or your sudo password. So enter it.
Then it will take a minute to install.
You can then run the program from your menu. It should be undeer internet applications.
Note: Most desktop linux distributions usually but not always already have a free telephony application installed.
Gnu telephony: http://www.gnutelephony.org/index.php/GNU_Telephony
Google Chat / Google Talk / Google Voice.