These days, atheism is quite the fad. Many young people take to atheism because they are fed up with the dogma and fanatism that is usually associated with traditional religions. They turn to atheism which is generally associated with Science, which in turn has an aura of being fair, rational, open, progressive, reliable and useful. Before we go into the details of why this trend and perception is based on incorrect information (by an atheist's own standard), let's quickly define some of the terms that we would want to use extensively in our discussion.
At the heart of any religion is its faith, which is a set of core beliefs based on which it defines, arrives at, and expounds the Truth, which it might further use to explain other phenomena, observable or otherwise. Further, a religion sets forth to its followers, certain methods and techniques which may be followed to reach the Truth as defined in its faith. We say atheism is a religion (or some may define it as a group or religions to account for internal differences in opinion), primarily because it is very similar to established religions in both these aspects. The core faith of atheism is in a universe that can be fully described by science in its narrow definition - in other words, a universe that has no influence that is beyond direct observations or logical inferences from them. This idea, though is drastically different from the core of most traditional religions which emphasize on the spiritual aspect of life and even use it as a starting point to explain the observable universe, is still a fundamental faith in atheist philosophy. Much like any other religion, it is by relying on this core of faith that the atheist seeks to uncover the Truth of this universe.
Based on its core faith, which is the validity and universal applicability of science and logic, the Atheistic religion provides as its own way, the scientific method and the way of logical reasoning. Of course, this does not prevent other religions which explore a spiritual aspect also from using science, or its methods, for explaining the physically observable realm of this universe. In fact, the origin of science as we know today can be traced back to the truth-seeking efforts of its very religious pioneers in the ages when seekers of knowledge in the physical realm where not dogmatically convinced that there is no truth beyond it. Many of the theistical religions also share Atheism's liking for science, but at the same time understand its self-imposed limitation of dealing only with the objects of the five senses, and employ equally rigorous and systematic methods in dealing with subtler realms. In believing that logic and science can answer all questions about the universe, and in rejecting anything that doesn't fit into logic as false, science and logic perhaps take the position as chief Gods in the Atheist pantheon. This is not strikingly different from other religions which consider god as being love, bliss, truth, virtue, or an embodiment of such virtues or their combinations.
Religion, by itself, is not dogmatic or fanatic, and nor is Atheism. Followers of many religions, on the other hand, are often found to assert, quite fanatically, that their way and perception of the truth is the one and only one - all else being falsehood leading to hell. This, as observed in the Role of Religion, is a negation of the true spirit of any religion. Atheism also has a fair share of such blockheaded followers and they have their own prophets who insult the ideas of other religions and blame them for all the evils in the society. They think of themselves (and other atheists) as a separate class of people who are higher and more intelligent than the followers of other religions - so much, that they consider their convictions to be above all other religions, free from their faults, and as the only path that can lead to the Truth or promote harmonious existence. To think of one's own path to be the true path is okay; but insulting others who do not follow it is the most obnoxious face of dogma, and it is not less so when displayed by an Atheist. The worst enemy of any religion are not its critics but its own followers who would, rather than understand its true essence and apply it to enrich their lives, attempt to attack and prove other religions wrong.
It can be seen in the history of many religions that they started off as being the oppressed, and at a later point became the oppressor themselves. For example, Jesus Christ was persecuted for what he believed and preached, and the Church which claimed to follow and represent him persecuted many in later ages for not falling in line with their beliefs (or using this as an excuse). There have been times when followers of Science, such as Galileo, have been persecuted by intolerant followers of powerful theistical religions; the way Science is being hijacked by some equally intolerant followers of Atheism, the day may not be far away when we read of Scientific Inquisition and Jihad being advocated by the proponents of this new religion. Persecution, abuse and intolerance of differing ideas is not the property of any religion, but of people who seek to achieve and maintain power over others. Even if we abolish the use of the term religion altogether (its essence cannot be abolished for as long as humans have an unquenchable thirst for knowledge), such people would find other means to control and dominate others, as we have seen in the case of many Communist regimes.
So in all the three most common aspects of religion, we see that Atheism is just like any other religion (or may turn out to be a group of them as the number of its followers increases). Like we classify some religions as monotheistical and polytheistical, perhaps a higher level of classification into theistical and atheistical religions will make sense. But I don't see any reason (yes, reason is not a prerogative of atheists) to subscribe to the views of many an atheist that atheism is not a religion, but something above and beyond it.