Ekiga is a SIP and H.323 compatible VoIP, IP Telephony, and Video Conferencing application that allows you to make audio and video calls to remote users with SIP or H.323 hardware and software. It supports all modern VoIP features for both SIP and H.323.
SIP Communicator is an application that allows you (or rather would soon allow you ;) ) to do audio/video conversations over the Internet through the SIP protocol, as well as chat with your friends using some of the most popular instant messaging protocol
SIP Communicator 1.0 is an application that allows you (or rather would soon allow you ;) ) to do audio/video conversations over the Internet through the SIP protocol, as well as chat with your friends using some of the most popular instant messaging prot