Since Ubuntu does not update Pidgin, the pidgin website has issued a PPA. But I could not update it even by that. So I tried to compile from source.
Firstly you have to download the source from pidgin website from here.
Or get it as user from your terminal in this way:
Save the downloaded file to your home directory. Then follow these instruction in Install from Tarballwget http://sourceforge.net/projects/pidgin/files/Pidgin/pidgin-2.6.1.tar.bz2
tar -xvjf pidgin-2.6.1.tar.bz2
cd pidgin-2.6.1
After the Second step (i.e ./configure) you have to get this line

Build with voice and video.... : yesIf you don't get this line then you wont be able to voice chat. It means you are missing some plugins of Gstreamer or you have not installed some required dependencies which are optional for pidgin installation.
The required packages for your pidgin to support voice and video are:
- gstreamer0.10-plugins-good
- gstreamer0.10-plugins-bad
- gstreamer0.10-plugins-farsight >= 0.12.6
in addition to the extra compiling requirements of:
- farsight2-0.10 => 0.0.8
- gstreamer-plugins-base-0.10-dev
sudo apt-get install gstreamer0.10-plugins-good gstreamer0.10-plugins-bad libgstreamer-plugins-base0.10-dev gstreamer0.10-plugins-farsight libgstfarsight0.10-0 libgstfarsight0.10-dev
After complete installation, run the ./configure again. You should now get the required output. If you stuck up somewhere in the middle then you probably have to install few more dependency packages. For the required dependency packages to install pidgin check this link here. You can also run this command if nothing goes well.
If still you dont get the required output then it means that Ubuntu is not fetching the latest releases of the Gstreamer. Which happened with me. So I downloaded all the source files and compiled them and then installed them. At last when I did ./configure I got the required output. Then I went on to compile and install pidgin from source with the latest releases.sudo apt-get build-dep pidgin
They are:
libnice-0.0.9
farsight2-0.0.14
gst-plugins-base-0.10.24
gstreamer-0.10.24
Compile and install the above packages in the same order and then run the ./configure of pidgin-2.6.1 again and check the output. To know how to compile and install click here. Before running "make install" remove the pidgin from your system.
sudo apt-get purge pidgin pidgin-data libpurple0 libpurple-binIf you still need any help then please use the comment link below to ask you queries. I will try my best to help you out.
Running voice and video chat:
Currently there is no way to configure your microphone or webcam in this release. You can do so by running this command from the terminal.
gstreamer-properties
This should work out.
To start Voice and Video you have to open the conversation window > Conversation > Media
Currently I have problems running voice and video chat. Working out to get it done. Watch this page for updates.
Update:
http://ubuntuforums.org/showthread.php?t=1244589
Update 2:
Now you don't have to do anything. Just update your pidgin from your repository with the help of your package manager. Ubuntu has updated it for you. Thanks for Ubuntu guys.
Just do this:
sudo apt-get install pidginYou are done.