Facebook have some inbuilt emoticons just like yahoo messenger which are not known by many people. Use this shortcut keys of emoticons in the chat-box of face book for cool emoticons and for fun.
Some of the secret code of facebook emoticons are given below. So have a cool chat with your friends with cool emoticons.Enjoy!!!! You can also try the http://facemoods.com/ and install a Addon for your Facebook within the Firefox for even more Emoticons. :)