Ekiga 4.0.1

Ekiga is an open source SoftPhone, Video Conferencing and Instant Messenger application over the Internet. Ekiga supports HD sound quality and video up to DVD size and quality. It is interoperable with many other standard compliant softwares, hardwares and service providers as it uses both the major telephony standards (SIP and H.323).

Main Features of the Ekiga Softphone in a nutshell:

Ease of use with a modern Graphical User Interface
Audio and Video free calls through the internet
Free Instant Messaging through the internet with Presence support
Audio (and video) calls to landlines and cell phones with support to the cheapest service providers
High Definition Sound (wideband) and Video Quality up to DVD quality (high framerate, state of the art quality codec and frame size)
Free of choice of the service provider
SMS to cell phones if the service provider supports it (like the default provider)
Standard Telephony features support like Call Hold, Call Transfer, Call Forwarding, DTMF
and much, much more....