http://mumble.info/
#mumble on freenode
Mumble is a voicechat program for gamers written on top of Qt and Opus.
There are two modules in Mumble; the client (mumble) and the server (murmur). The client works on Win32/64, Linux and Mac OS X, while the server should work on anything Qt can be installed on.
Note that when we say Win32, we mean Windows XP or newer.
On Windows, after installation, you should have a new Mumble folder in your Start Menu, from which you can start Mumble.
On Mac OS X, to install Mumble, drag the application from the downloaded
disk image into your /Applications folder.
Once Mumble is launched, you need a server to connect to. Either create your own or join a friend's.
Murmur should be run from the command line, so start a shell (command prompt) and go to wherever you installed Mumble. Run murmur as
murmurd [-supw <password>] [-ini <inifile>] [-fg] [v]
-supw Set a new password for the user SuperUser, which is hardcoded to
bypass ACLs. Keep this password safe. Until you set a password,
the SuperUser is disabled. If you use this option, murmur will
set the password in the database and then exit.
-ini Use an inifile other than murmur.ini, use this to run several instances
of murmur from the same directory. Make sure each instance is using
a separate database.
-fg Run in the foreground, logging to standard output.
-v More verbose logging.
Murmur is distributed separately from the Mumble client on Mac OS X. It is called Static OS X Server and can be downloaded from the main webpage.
Once downloaded it can be run in the same way as on any other Unix-like system. For more information please see the 'Running Murmur on Unix-like systems' above.
Doubleclick the Murmur icon to start murmur. There will be a small icon on your taskbar from which you can view the log.
To set the superuser password, run murmur with the parameters -supw <password>.
Mumble will use 10-40 kbit/s outgoing, and the same incoming for each user. So if there are 10 other users on the server with you, your incoming bandwidth requirement will be 100-400 kbit/s if they all talk at the same time.