Actually, now that I look for it, it isn't there anymore... It used to be in the main directory in minecraft.jar, right next the the normal char.png. I've looked through the whole archive and I can't find it, it must have been removed in a recent update.
Private Mod Note
Rollback Post to RevisionRollBack
Minecraft is the meth of video games, try it once and you're hooked, and you'll stay up for 3 days when you're on it.