Here are the standard Gmail emoticons that animate from their side-to-upright views. The only thing I changed was placed them all in an endless loop rather than having them stop once they were upright.
(working on Windows XP/Vista, with Pidgin 2.5.4)
update (Feb 11): I added the animation from upright to their side views, so that they just didn't restart. It looked a little jumpy, but hopefully you guys like this better