Getting and Installing Mumble
This page shows you directions on how to install Mumble (client) as well as Murmur (server).
Just head to SourceForge downloads page, get the Windows executable and run it. Follow the installer instructions and you are done. The installer includes both the client and the server.
Mac OS X
Precompiled Mac OS X universal binaries are available from the SourceForge downloads page.
Debian unstable has the latest release at all times in the unstable repository, and snapshots in experimental. Backports to current stable are done as soon as the packge reaches testing (usually a week after release).
To configure the server, just 'dpkg -reconfigure mumble-server'.
Ubuntu carries whatever Mumble version was current at the time of the release in the universe repository. Backports of current releases can be found in the PPA.
Uptodate packages can be found in the Build Service.