Wedding ceremony customs

In British tradition, the best man has a traditional duty of keeping track of a marrying couple's wedding ring(s) and to produce them at the symbolic moment of the giving and receiving of the ring(s) during the traditional marriage ceremony.
In more elaborate weddings, a ring bearer (usually a young boy that is part of the family of the bride or groom) may assist in the ceremonial parading of the ring(s) into the ceremony, often on a special cushion or pillow(s).
In older times, the wedding rings did not only signify a sign of love, but were also linked to the bestowal of 'earnest money'. According to the prayer book of Edward VI: after the words 'with this ring I thee wed' follow the words 'This gold and silver I give thee', at which point the groom was supposed to hand a leather purse filled with gold and silver coins to the bride. [3]
Not only in England was the wedding ring considered more connected to the exchange of valuables at the moment of the wedding than a symbol of eternal love and bondage but in most other European countries as well. Sometimes it went as far as being a conditional exchange as this German formula shows: 'I give you this ring as a sign of the marriage which has been promised between us, provided your father gives with you a marriage portion of 1000 Reichsthalers'. [3]
In some European countries, the wedding ring is the same as the engagement ring and changes its status through engraving and the change of the hand on which to wear it. If the wedding ring is different from the engagement ring, the question whether or not the engagement ring should be worn during the ceremony leaves a few options. The bride may wear it on her left ring finger and have the groom put the wedding band over it. She may also wear it on her right ring finger. The bride may also continue wearing the rings on different hands after the wedding – this may prevent the engagement ring from scratching and scuffing. Another option is to have the main bridesmaid keep the ring during the ceremony – there are a variety ways to keep it: in a pouch, on a plate, etc. After the ceremony, the ring can be placed back on either the left or the right hand.

Pre-Wedding Customs

According to some customs, the wedding ring forms the last in a series of gifts, which also may include the engagement ring, traditionally given as a betrothal present. Other more recent traditions, encouraged by the jewelry trade, seek to expand the idea of a series of ring-gifts with the promise ring, often given when serious courting begins, and the eternity ring, which symbolizes the renewal or ongoing nature of a lasting marriage, sometimes given after the birth of a first child; and a trilogy ring, usually displaying three brilliant-cut round diamonds each, in turn, representing the past, present and future of a relationship.
A European tradition encourages the engraving of the name of one's intended spouse and the date of one's intended marriage on the inside surface of wedding rings, thus strengthening the symbolism and sentimentality of the rings as they become family heirlooms.
Among Eastern Orthodox and Eastern Catholic Christians, the exchange of rings are not technically part of the wedding service, but rather are exchanged at the betrothal. It is always a two-ring ceremony. Traditionally, the groom's ring will be made of gold, and the bride's ring made of silver,[1] and are blessed by the priest with holy water. The priest blesses the groom with the bride's ring, and places it on the ring finger of his right hand; he then blesses the bride with the groom's ring and places it on her finger. The rings are then exchanged three times either by the priest or by the best man.[2] While in modern times, the ceremony of betrothal is often performed immediately before the wedding (or "crowning" as it is more properly called), the actual symbolic act of marriage is not the exchange of rings, but the placing of crowns on the head of the bride and groom, and their partaking three times of the "common cup".

source: www.wikipedia.org