I'm going to assume everyone knows this, but will mention it because I know of at least one person who didn't know it.
The smiley's that you see are just the way that "your" phone interprets the characters
or :-( etc. The person you are sending to will see them the way that their phone interprets them. The actual message only contains the text characters.
I remember someone way back with the Droid who could not understand why their friend on a BB did not get the Bot Smileys they were sending them. You don't send the actual icons, you only send text which is then translated to the specific set of icons your phone uses.