Yes, I wish I could choose it from iMeesages pull down menu "choose smiley" but it is easy enough to open the Emojis viewer window by clicking the smile face icon on the top bar, next to time machine, bluetooth, sound, language, date/time etc. (at least it worked on my MacBook Pro). Only thing you got to do is just drag your choice of smily to where you want to insert it.
PaulazMom about Emoji Emoticons