Pidgin themes, Pidgin smilies, Pidgin sounds
To install the "plurk emoticon" smilies set, you should download it using the link below, unzip files and place it into themes folder. That folder's location depends on OS you use.
%appdata%\.purple\themes
Extract the content of the downloaded file into the "~/.purple/themes" folder and select new smilies theme in the Pidgin preferences.
Note: "~" is your "home" directory in Linux, i.e. /home/username. To see the ".purple" folder in there, you might need to enable "Show hidden files" option in your preferred file manager.