Latest version of Gajim is 0.15.4
A 0.16-rc2 version is in test
If your distribution doesn't have the latest version you are advised to use the autopackage or the source tarball

Debian GNU/Linux

If you use Debian unstable do apt-get install gajim
The Debian package of 0.16-rc2 is here.
A daily package from mercurial is also built. To use it, remove gajim (apt-get remove gajim), add this line to your /etc/apt/sources.list:
deb ftp://ftp.gajim.org/debian unstable main
and install it by doing apt-get install gajim-nightly. You can get the GPG key of this package by installing gajim-dev-keyring package from the same repository. Just do apt-get install gajim-dev-keyring.

Slackware

You can get the Slackware package of Gajim here.

Ubuntu

If you use Ubuntu universe repository do apt-get install gajim
If you want newer version of Gajim, you can also use this PPA

Fedora

Just yum install gajim

Gentoo

Just emerge gajim

Archlinux

Just pacman -S gajim

SUSE

One click install for openSuSE 12.2, 12.3
For other versions, get it here

PLD

Just poldek -U gajim

SourceMage

Just cast gajim

Mandriva

Just urpmi gajim

Zenwalk

Just netpkg gajim

AgiliaLinux (MOPSLinux)

Just mpkg-install gajim

FreeBSD

Gajim is available in FreeBSD via FreeBSD ports. Just cd /usr/ports/net/gajim/ && make install clean. Find out more.

Autopackage

Soon available here.

Windows installer

There is a Gajim installer.
Here is a Gajim installer for 0.16-rc2 version .

Source

The tarball version of Gajim is here. For information on how to build Gajim, see the README (in English).
The tarball version of 0.16-rc2 is here.
If you want to use the last unstable development version, then you should checkout the mercurial repository.

Mercurial

The mercurial repository is available at this address: http://hg.gajim.org/gajim and viewable here.

Under GNU/Linux

In order to download Gajim sources, here is what you have to do: You first have to install mercurial (apt-get install mercurial under Debian)
Then in a console, enter the following commands:

hg clone http://hg.gajim.org/gajim gajim

Install dependencies, and build Gajim. Please see the README (English) for details.

You can run Gajim by typing the following:

cd gajim and then ./launch.sh

Once you have the repository, you can update it periodically so it matches the latest version from the main repository with the following command:

hg pull && hg update

Under Windows

You first have to install mercurial for windows. In order to do that, download the binary here
Once mercurial is installed, the commands are the same with those under GNU/Linux. Only difference is instead of launch.sh you run launch.bat. Enter them in an MS-DOS command line and you're done.
To run Gajim, you need external libraries. You can find a tutorial on the way to install them On the Wiki.

Daily Snapshots

Everyday on 01:00 (GMT+1 time) gz tarballs are produced from mercurial. You can use them if hg is broken for you at the moment. Here to get them.

Old releases

You'll find old releases of Gajim here.