Empathy and Pidgin support video and audio chats over Google Talk/Jabber/XMPP protocol. You could also give the recently launched Google Video and Voice Chat an try.

Skype also supports video and voice chat on Linux.

Or you could use Ekiga (VoIP client) for video and voice.

Gyachi has this on their web page:

This Yahoo! client for Linux operating system supports almost all of the features you would expect to find on the official Windows Yahoo! client: Voice chat, webcams, faders, 'nicknames', audibles, avatars, display images, and more. Yet, it remains very light-weight and memory-friendly.memory-friendly.

Meebo is a web service that supports voice and video chats on Linux.

The package g2ipmsg is available in the repositories - v0.9.6 for all versions of ubuntu except for oneiric. Thus to install in versions prior to oneiric or for 12.04 and above:

g2ipmsg

However its not available in Oneiric (11.10) because it doesnt compile under oneiric due to the changes to Gnome-Panel and the dependency on the gnome-2 applet libraries.

You could compile and install to produce this result in gnome-classic (no-effects)

Note - when the application starts - it starts minimised to the gnome-panel. For some reason, in Unity, this application does not appear - probably the minimised application is not directly visible in the Unity panel.

To get the application to work under Unity you need to enable the old sys-tray:

gsettings set com.canonical.Unity.Panel systray-whitelist "['all']"

Then logout and login before searching for g2ipmsg in Dash

I've compiled and added this to my PPA. If you wish to compile this yourself, then instructions are below.

Install from PPA

sudo add-apt-repository ppa:fossfreedom/g2ipmsg
sudo apt-get update
sudo apt-get install g2ipmsg

to run g2ipmsg

1. If you are using the Gnome-Classic interface, then G2ipmsg will be found in the Accessories menu option
2. If you are using Gnome-Shell then search in Activities for g2ipmsg and the application will start minimized in the system-tray notification area (bottom right) of the screen. You will need to move you mouse to that area to make the application icon visible. My recommendation would be to use the system-tray extension to make the application icon visible at all times in the top-right of the screen. See my link answer below for more information about these areas and how to install the extension
3. If you are using Unity/Unity 2D you will need to manually enable the system-tray area for the application to start in the top-right area of the screen next to the indicator area.

how to compile

• Get the sources:

cd ~/Downloads
wget https://launchpad.net/ubuntu/+archive/primary/+files/g2ipmsg_0.9.6%2Bdfsg.orig.tar.gz
wget https://launchpad.net/ubuntu/+archive/primary/+files/g2ipmsg_0.9.6%2Bdfsg-1.1.diff.gz

• Now install some prerequisites and libraries

sudo apt-get install build-essential devscripts cdbs debhelper autotools-dev libgnomeui-dev libgstreamer0.10-dev libxml-parser-perl libssl-dev

• Then uncompress and patch the sources

 tar zxvf g2ipmsg_0.9.6+dfsg.orig.tar.gz
 gunzip g2ipmsg_0.9.6+dfsg-1.1.diff.gz
 patch -p0 < g2ipmsg_0.9.6+dfsg-1.1.diff

• Compile to create deb packages

cd g2ipmsg-0.9.6+dfsg/
debuild -us -uc

• Install the deb package

cd ..
sudo dpkg -i g2ipmsg_0.9.6+dfsg-1.1_i386.deb

Note - if you are compiling 64bit - then the package name will end in amd64.deb

Linked Question:

1. How to open aMSN that has been minimised to the tray?