By 400 the simple way of celebrating communion used by the earliest Christians became more and more developed and complex. In time each city had its own way of offering the Holy Eucharist. Eventually as the church became more centralized communion became more standardized. The Divine Liturgy most frequently used today in the Orthodox Church is called the Liturgy of St. John Chrysostom. It follows the traditions of the city of Constantinople, where St. John Chrysostom (+407A.D.) served as Patriarch.
Here is a link to the Divine Liurgy of St John Chrysotom in it's entirety as used by the Orthodox church.
living water reprint from 2009