Linphone is an open source Voice Over IP phone (or SIP phone) that makes possible to communicate freely with people over the internet, with voice, video, and text instant messaging. Linphone makes use of the SIP protocol (an open standard for internet telephony) and can be used with any SIP VoIP operator, including our free SIP audio/video service.
See also:
Easy voice talk between 2 computers in 2 countries?"
