When you are entering your post, you'll see a link at the bottom right of the text entry box which says "formatting tips".
This shows you how to do lots of stuff, including smileys.
For example, if I wanted to put a smiley face, I would type : and then ) right beside it. This gives , but you won't see it until you save your comment.
Cheers, Eric G.
Edit: Geez - you're impatient aren't you!