The wedding ceremony music tends to be softer, usually classical wedding music or ballads. There should be about five songs played as a prelude when the guests are seated, then a special song when the mothers of the bride and groom are seated.
There are two songs during the processional, one when the bridesmaids enter, and the most dramatic as the bride walks up the aisle. The most joyous music is played in the recessional, when the bride and groom leave together.
There can be special songs at different points in the ceremony, such as after exchanging the rings and vows, lighting the unity candle, or taking communion. Some churches have rules about wedding songs used during your ceremony so be sure to ask your clergy person or officiant!