Ekiga
Ekiga (formerly called GnomeMeeting) is a VoIP and video conferencing application for GNOME and Windows. Ekiga supports both the SIP and (based on OPAL) protocols and is fully interoperable with…
Linphone
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.…