"In an effort to create a free software alternative to Skype the GNU Project has announced plans for GNU Call. The project hopes to provide secure over-the-internet calls to all users and rival the popular Skype VoIP service.
The GNU Project is one of the primary advocates and developers behind the free and open source software and provides a broad range of free software which is included in popular Linux releases.
The GNU Call project says that its primary difference with Skype will be that it will use a peer-to-peer SIP protocol so that the service will not rely on one single service provider. In doing so the organisation hopes to create self-organised mesh calling networks that will be beyond the control of any one organisation. This, the organisation says, will increase security and reliability as there will be no single vulnerable point.
The project will build on the already existing GNU SIP Witch, a server for SIP calls which provides a method of managing and routing calls.
The GNU Project's plans to create a distributed peer-to-peer version of Skype's service is similar to the Diaspora project's plans for an open source Facebook alternative. Bot projects are looking to provide a free (as in freedom) alternative to what are already well established services, which is a significant undertaking.
GNU Call is still in early development but what is known is that it will have the option for multiple user interfaces, so it can be integrated into most desktops, it will not include video directly into the application but will likely hand that off to standalone video players on the various desktops and will be usable on both desktops as well as smartphones.
The ambitions of the GNU Call team are noble, as many commenters on their site suggest, but breaking into the Skype market, even with the best product, is going to take hard work." (http://mybroadband.co.za/news/software/19177-GNU-Call-open-source-Skype.html)