1. An apparatus for compressing a Short Message Service (SMS) message, the apparatus comprising: an input unit through which characters are input by a user; a display unit which displays the characters input by the user; a control unit which compares the characters input by the user with a stored sentence table of recommended sentences to determine whether there is at least one recommended sentence among the recommended sentences of the sentence table that includes the input characters, and if it is determined that there is the at least one recommended sentence that includes the input characters, controls the display unit to display the at least one recommended sentences; a converting unit which converts a recommended sentence selected by the user from among the at least one recommended sentence displayed by the displayed unit into a compression code; and a transmission unit which transmits an SMS message that includes the recommended sentence converted into the compression code, wherein a size of the compression code for the recommended sentence selected by the user is a predetermined fixed size regardless of the number of words in the at least one recommended sentence, wherein the predetermined fixed size is used to determine whether a character or a sentence in the SMS message is a compression code.
7. The apparatus of claim 1 , wherein the control unit determines the used capacity of the SMS message by adding a used capacity of the recommended sentences selected by the user with a used capacity of general sentences input by the user into the SMS, wherein the used capacity of each of the recommended sentences selected by the user is two bytes, and wherein the used capacity of the general sentences input by the user into the SMS corresponds to the number of characters in the general sentences input by the user into the SMS.