invisibilitysyndrome : could you let us know what device and browser you're using?
On my setup using a desktop PC with Firefox:
There should be a smiley icon around the top middle of the reply window with all of the other formatting options.
Clicking the icon should slide open a panel below the Reply box with the list of available emoticons, click one to add it to the post, or click "Show All" underneath that to view the full list.
If you're on the Mobile site (blue/white IP.Board Mobile color theme) the interface is completely different and those options aren't there.
There's a light blue "Full Version" button @ the bottom left to change to the full Desktop site where you'll see those options.
Emoticons can also be entered by directly typing the code for that emoticon: