jaj sorry, som zabudol, dopln na zaciatok poslednych dvoch uvedenych riadkov sudo, teda
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 67265eb522bdd6b1c69e66ed7fb8bee0a1f196a8 ;
echo deb http://ppa.launchpad.net/pidgin-developers/ppa/ubuntu `lsb_release --short --codename` main | sudo tee /etc/apt/sources.list.d/pidgin-ppa.list ;
sudo aptitude update;
sudo aptitude install pidgin