I know there are several good articles about Slava online and I was just reading one that I thought was good. I'll post it below.
The word slava means celebration. This Serbian Orthodox observance is called Krsna Slava and is similar to (Krsno Ime - Name Day) in other Orthodox Christian traditions.
Christian missionaries not only converted Serbs to Christianity; but "Christianized" the spiritual customs they practiced as well. In this way the missionaries satisfied the peoples' psychological as well as spiritual needs. Because of this and other proven benefits of the Slava among Serbs, the people yet sing today, Niko Nema Sto Srbin Imade!
While most people observe the anniversary of their birth, the Serbs observe the Slava. In a spiritual sense the Slava stands above a chronological birthday. In fact, history and tradition tell us that the Slava came into existence among the Serbs with their acceptance of Christianity. Centuries ago, when a Serbian family accepted Christianity the Saint commemorated by the Church on that day became the family's patron Saint; that day each year then became a special observance. It was the birthday of their faith in Christ, perpetuated from one generation to the next through the male members of the family.
Among the most common Saints' names for the Slava one finds the names of St. Nicholas the Wonder-worker, St. George the Great Martyr, St. John the Baptist and Forerunner, St. Archangel Michael, Sv. Sava the First Serbian Archbishop, Sv.Petka and many others.
There is a saying among Serbs, Ko Slavu slavi tome Slava mu i pomaze! In translation this means, Whoever celebrates the Slava, him the Slava helps! Rightly so, for according to the teaching of the Church, the Church is the communion of all the Saints, in which Christ abides. There is strong evidence that the intercession of the Saints is effective. Accordingly, St. Paul advises us saying, "Give thanks to the Father, who has qualified us to share in the inheritance of the Saints in light" (Col. 1:12).
Besides individuals and families, one finds many cultural and social organizations, cities, and even military units observing Slava. Often when two Serbs who do not know each other meet, one way of introduction is to ask about the family's Slava. The Slava has played an important role in the life of the Serbian people throughout its history. Situated at the meeting point between two important cultures, namely the Byzantine East and the Latin West remaining distinct from them both in addition to being subjugated into slavery by the Moslem Turks for over five centuries, the Serbs associated the Slava with survival and the preservation of their ethnic identity. Perhaps it is for that reason we hear the song: Niko Nema Sto Srbin Imade!
Indeed the Slava is a day of great rejoicing. Relatives, kamovi, and friends begin arriving the day before the Slava and many remain until the following day. An important aspect of the celebration is the religious observance of the patron Saint. In a Serbian Orthodox home one finds the icon of the patron Saint of the family illuminated by the flicker of a votive light. This in a sense is a place of prayer for the family. A Slava candle is lighted on that special day and the Slavski Kolac (Slave Cake) is presented for prayers of blessing, along with a glass of wine. Each of these items has symbolic meaning: the candle represents the light of life in God.
The bread symbolizes Christ our God, who said, "I am the living bread which came down from heaven" John 6:51); finally, there is a dish of boiled wheat (koljivo), which is blessed and served in memory of deceased family members. The candle is never blown out but is extinguished with wine. The same glass is then handed around the family circle and each member takes a sip of it, thereby symbolizing the perpetuity of the Slava. The scent of the incense binds together the emotions of all present on this unique and festive occasion.
While the festive meal is in progress, the host does not sit but remains available in service to all. He serves his Krsno Ime, then many beautiful and well-wishing toasts (Zdravice) are offered
Slavski Kolac for the health and prosperity of the household. Music is provided by a one-stringed instrument called the Gusle, accompanied by the voice of the Guslar. The favorite subjects of these ballads are drawn from the rich heroic history of the Serbs.
The Slava has remained as one of the proven values and customs of the Serbian people. It may be said that the Slava played an important role in Serbian history, helping them to withstand centuries of religious proselytism and persecution from the Latin West, as well as slavery and brutality from the Islamic East. The spiritual, social, and preservational role of the Slava remains undiminished for the Serbian people to this day. http://www.st-george-church.org/English/Krsna_Slava.htm