What encoding is text messaging in? The reason for the question is that I have a friend with an iPhone who sends emoticons, and I receive them as a single rectangular box.  I wonder if it's an encoding problem.
iPhone emoticons are not character combinations like :-) but they are single UTF-16 character of emoticons called Emoji which are not by default supported in Android.

By using some third party sms apps such as GO SMS PRO and installing its Emoji Plugin you would be able to send and receive such iPhone emoticons to/from your friend.