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. GyachE Improved uses Gtk-2 for its user interfaces (Gtk-2 2.0.6 or better required).
To install GyachE Improved in ubuntu jaunty
Open sources.list
$ vi /etc/apt/sources.list
Add these lines to sources.list
deb http://ppa.launchpad.net/loell/ppa/ubuntu jaunty main
deb-src http://ppa.launchpad.net/loell/ppa/ubuntu jaunty main
Now update apt-get.
$ sudo apt-get updat
Install Gyachi
$ sudo apt-get install gyachi
Other linux users please see http://gyachi.sourceforge.net/download.shtml