TeamTalk is a free voice conferencing program which lets each user adjust their audio quality to maximise the experience for everyone. Another nice touch is that instead of relying on a central server, you can set up your own personal server, if you are confident enough about your bandwidth capabilities. There’s also a PocketPC version for mobile chatting. Cool.
TeamTalk is available for desktop PCs running Windows and for Windows-based Pocket PCs. TeamTalk comes with its own standalone server which can be used both in LAN and internet environments. The server is available for Windows, Linux and FreeBSD. Unlike many other internet voice conferencing applications (and internet phones) TeamTalk allows any number of people to participate in a conference and channels/rooms can be used to organize these conferences. Having numerous people in a conversation sets high demands to your network connection’s capabilities but TeamTalk features a variety of configuration options which allows you to select the audio quality that best fit your connection speed.