Emoticons and Emoji

Pandora's default set of emoticons was drawn by the artist who goes by the name maze.
You can expand that set and add your custom emoticons.
There are many sites where you can find emoticons, [some are extracted from IM clients, the others are the original artwork (checkout the terms, most of them are free for personal use)], such as this one:
http://hundone.deviantart.com/art/Pidgin-Old-Tango-Smilies-63215859

Pandora does support animated gifs as emoticons so you can use those as well. These appear to be more prominent in Internet forums (such as this one), sometimes are not drawn too well so you may have to search more.

To add you own emoticons:
1. Close Pandora.
2. Browse to folder Emoticons, located inside the root of your main data folder.
3. Move custom emoticons (extracted image files) to that folder.

Emoji in Plain Text Messages and Message Summaries

Emoji's are supported as well, but in order to see them (in message summaries or plain text messages) your font has to include emoji-characters. Font that supports emoji, starting with Windows 7, is Segoe UI Symbol. So change plain text message font/message summaries default font to Segoe UI Symbol, or other emoji-supporting font.

Emoji in HTML Messages

The above does not apply for HTML messages, where emoji are always visible.
Note. If emoji menu item includes the image and the character, use Shift key to display inserted emoji in it's original form (as Unicode character).