Ekiga is a VoIP, IP Telephony, and Video Conferencing application that
allows you to make audio and video calls to remote users with SIP or
H.323 compatible hardware and software.  It supports many audio and
video codecs and all modern VoIP features for both SIP and H.323.
Ekiga is the first Open Source application to support both H.323 and
SIP, as well as audio and video.  Ekiga was formerly known as
GnomeMeeting.

Web sites related to Ekiga:
- home page: http://www.ekiga.org
- documentation, FAQ, troubleshooting, binary snapshots etc.: http://wiki.ekiga.org
- free SIP accounts: http://www.ekiga.net