Free Phone is an audio tool for the Internet developed by the IP Audio Freaks at INRIA.

FreePhone includes a number of interesting features

Management: Support for multiple concurrent unicast and multicast conversations, FreePhone “white pages” on the Web, simple call protocol.
High quality audio capture: Up to CD/DAT stereo quality capture, wide panoply of coding schemes.
High quality restitution: 3D/spatial rendition of audio sources (this feature is used in conjunction with the MiMaze distributed (multicast) game to enhance the sense of immersion in the game and to add live 3D voice interaction between players — however the feature is not available on the public release of FreePhone yet).
Adaptation to network conditions: Includes a rate control mechanism (adaptation to available bandwidth), a FEC-based error recovery scheme (adaptation to and recovery from loss process in the network), and an adaptive playout adjustment scheme (adaptation to delay variations).