As jckstraw mentioned, "...the Fathers comment on the creation account, telling us that the days were literal days...", and this is indeed true of many of the Fathers, while others actually took the days as allegorical. However, even the most extreme of the allegorical interpreters such as Origen and Clement of Alexandria still believed that the world was less than 10,000 years old.
Even the modern Saints and Holy Elders, such as St. Barsanuphius of Optina, St. Nektarios, St. John of Kronstadt, St. Justin Popovich, St. Nikolai Velimirovich, Fr. George Calciu, Fr. Seraphim Rose, Elder Joseph the Hesychast, Elder Cleopa, Elder Paisios, and others seem to support a young Earth. I have yet to see a Saint or Elder, either ancient or modern, support the kind of time frame that theories of evolution* require (aka "Old Earth".) A young Earth (6,000-15,000 years, more or less) seems to be the clear consensus of the Saints and Holy Elders, both ancient and modern.
I, for one, am not ready to claim that the Holy Saints throughout the ages taught from their own vanity. They taught from Holy Scripture, not from their own imaginations, and not from "science"... In fact, they often taught the "Young Earth" view in clear opposition to the "sciences" of their own times. No quote is more clear than Saint Basil the Great when he said, "One day, doubtless, their terrible condemnation will be the greater for all this worldly wisdom, since, seeing so clearly into vain sciences, they have wilfully shut their eyes to the knowledge of the truth."
Science is a methodology that is used by people in an attempt to answer questions through empirical observation and naturalistic reasoning. The scientific method has been developed based on a few major premises: One: We can only know what we can observe. Two: People's powers of observation are imperfect (experiments must be repeatable). And three: The laws of nature are consistent throughout space and time, therefore conclusions drawn from experiment and/or observations can be used to explain past phenomena.
Creation, however, according to Orthodoxy, can in no way meet those criteria. One, Creation canot be observed, this is axiomatic. and two, according to Orthodoxy, Creation was a direct act of God, and miraculous. This means that the laws of nature were quite probably not even in effect at the time of creation. We cannot measure, observe, and experiment on the creation of the universe, or the creation of man. We can only dig up pieces of the puzzle and assume things based on preconceived notions.
But only One was present at all of it. Only He has the whole picture. He is the One who we read of in Exodus, "the LORD spoke to Moses face to face, as a man speaks to his friend." And in the book of Numbers, He says about Moses, "I speak with him face to face, Even plainly, and not in dark sayings". What God told Moses about the beginning of the world was real and plain. So-called "scientists" on the other hand, are working in the dark, and try to make the random pieces they pick up here and there look as if it is the whole picture.
On the other hand, the real science behind evolution* is facinating. I quite enjoyed On the Origin of Species, and the various other lectures I've heard and books and articles I've read. Without the Saints and Holy Scriptures, I could easily be convinced that the theory of evolution* is fact. But as it is, I simply think that the science is missing some key evidence to draw a truly comprehensive conclusion.
As Saint Peter tells us, "And so we have the prophetic word confirmed, which you do well to heed as a light that shines in a dark place, until the day dawns and the morning star rises in your hearts; knowing this first, that no prophecy of Scripture is of any private interpretation, for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit." (2 Peter 1:19-21). So when I look at the words of Genesis 1-3, I will listen to the holy men of God, instead of taking the work of scientists who intentionally rule out any miraculous explanation. But at the same time, I do not reject any field of science, even if I do question some conclusions that have been made, especially when those conclusions so clearly undermine what these holy men of God have taught from the beginning.
But to touch on Michael the Iconographer's very valid concern... I do have to mention that if I believe the truth about Creation and ostracize those who are in error and declare them heretics, mine is, by far, the greater sin. We can discuss our positions, and the reasons we hold these positions, while still loving each other. We don't have to understand everything perfectly to be Orthodox Christians. If we did, there would be no room for me in the Church. While the above is what I truly beileve is the correct way to understand the current topic, I am in no way suggesting that those who disagree with me are anathema or outside of the Church in any way... I just think they have a misguided focus that will be corrected, either in time or in Eternity.
* Please note that I am not speaking of what is often called microevolution, for this is an observed, tested, and factual phenomenon. I am not even speaking of macroevolution, as several forms of speciation have been observed and recorded. "Kinds", as God created the animals, and "species" as defined in biology are not necessarily the same things. So I suppose I must admit that my problem is not properly with evolution itself, but with the idea of common descent, or any explanation of all life on earth that requires us to reject Scripture, as our God-Bearing Fathers, under the influence of the Holy Spirit, have explained it to us. Putting all of this under the title "evolution" may be poor form, but it is what I believe most anti-evolutionists, Orthodox ones anyway, really mean when they argue against evolution.