calls between Skype users are free) and you can make paid audio calls to landlines if you so choose.
More » ) is a video calling app for Linux and Windows computers.
It supports HD sound quality and (full screen) video that has a quality comparable to DVD.
One neat feature when doing that is that you can see which of your contacts are using Facetime (you can't call someone unless they're also signed up for Facetime).
More » Another similar way to make free HD video calls from your computer is with Nimbuzz.
that let you make completely free video calls and video chat sessions through your desktop or laptop computer?