"The goal of this project is to create a configuration-free P2P Skype replacement. Configuration-free means that the user will simply have to open the program and without any account configuration will be capable of adding people to his or her's friends list and start conversing with them. There are many so-called Skype replacements and all of them are either hard to configure for the normal user or suffer from being way too centralized."
https://tox.im/
While we're at it, the rest of the suggestions may be useful: http://www.reddit.com/r/dredmorbius/comments/27d5xr/please_f...
From the FAQ, this I like:
"The goal of this project is to create a configuration-free P2P Skype replacement. Configuration-free means that the user will simply have to open the program and without any account configuration will be capable of adding people to his or her's friends list and start conversing with them. There are many so-called Skype replacements and all of them are either hard to configure for the normal user or suffer from being way too centralized."
A lot.
(Emphasis added).