With Skype’s free software and your internet connection —
You can make FREE calls over the internet, chat, instant message, and make video calls. You can also make calls to phones and mobiles at home and abroad at great rates too.
Skype is free, easy and quick to download and install. Learn more about Skype
It works with Windows, Mac OS X, Linux and Pocket PC, and contains absolutely no spyware, adware, malware or anything like that.