Mumble is an open source voice chat application for groups. While it can be used for any kind of activity, it is primarily intended for gaming. It can be compared to programs like Ventrilo or TeamSpeak. Host your own server, let users create and manage channels for games and teams or record your own talks.
There are two modules in the Mumble package: the client (Mumble) and the server (Murmur). The superior audio quality comes in large parts from Speex, a high quality voice codec and DSP library for echo cancellation and denoising.