Mumble

Mumble is a voice chat application that lets you communicate with fellow players over the Internet. It also features a text chat with text-to-speech capabilities. The software consists of a client (Mumble) and a server (Murmur), this way the communication channel is open all the time and players can freely join and leave in contrary to peer-to-peer software, e.g. skype.

Mumble is not that widespread and few commercial servers are available but the user base is constantly growing. The sound quality and the latency is good and configuring the servers, permissions and channels, is easily done within the application.

Comments

It's a great tool and the Debian package makes the setup rather easy:

The package is available in lenny and sid. Install as root with:

apt-get install mumble-server dbus-x11

dbus-x11 contains the dbus-launch script that we need as well.
We can initialise the server as normal user with:

murmur-user-wrapper -i

This will create a folder murmur in our home directory with a file murmur.ini. Edit this file to e.g. change the default port 64738 if you have more servers.
Then we need to set a password for the superuser:

murmur-user-wrapper -p PASSWORD

After that we can start the server with:

murmur-user-wrapper

and login with the user name: SuperUser and the PASSWORD to edit user permissions and channel configuration, that is documented in detail here: http://mumble.sourceforge.net/ACL_and_Groups .

We can stop the server with:
murmur-user-wrapper -k