One of the most dangerous judgments on those who do not have a religion ... is that without religion you have no moral compass.
You're right, Emoni. But this common and profound misconception is fairly easy to refute--at least for those willing to listen to reason. (It doesn't necessarily have to impinge on religion, either, because it is not to religion's shame that the shamans and priests adopted existing moral precepts as good guidance for believers.) One useful book on the subject is Marc Hauser's MORAL MINDS.
The following pertinent material is from the Atheist Nexus site, Dr. Terence Meaden's discussions:
ORIGINS OF RELIGION, MORALITY AND BELIEF
"If we go back to the beginning we shall find that ignorance and fear created the gods; that fancy, enthusiasm, or deceit adorned or disfigured them; that weakness worships them; that credulity preserves them, and that custom, respect and tyranny support them in order to make the blindness of men serve its own interests."
--Baron D'Holbach
On Natural Morality:
If human morals and values do not arise out of divine command, then where do they come from? They come from our common humanity. They can be properly called humanistic.
A considerable literature exists on the possible natural (biological, cultural, evolutionary) origins of morality. Darwin saw the evolutionary advantage of cooperation and altruism. Modern thinkers have elaborated on this observation, showing in detail how our moral sense may have arisen naturally during the development of modern humanity.
We can even see signs of moral, or proto-moral behavior in animals. Vampire bats share food. Apes and monkeys comfort members of their group who are upset and work together to get food. Dolphins push sick members of a pod to the surface to get air. Whales will put themselves in harm's way to help a wounded member of their group. Elephants try their best to save injured members of their families.
In these examples we glimpse the beginnings of the morality that advanced to higher levels with human biological and cultural evolution. You may call them instinctive, built into the genes of animals by evolution. But this is a plausible mechanism for the development of human morality as well—a purely natural process, arising out of matter alone. Nothing 'spiritual' is involved because there is no substance separate from matter that we can call 'spirit'. (I suggest the name of this magazine be changed to Science & Nothing.)
It seems likely that this is where we humans have learned our sense of right and wrong. We have taught it to ourselves.
from "Do Our Values Come from God? The Evidence Says No." Victor J. Stenger. August 2005
Religion can be seen as another special ingredient of human societies, though one that emerged thousands of years after morality. There are clear precursors of morality in nonhuman primates, but no precursors of religion. So it is reasonable to assume that as humans evolved away from chimpanzees, morality emerged first, followed by religion. "I look at religions as recent additions," he said. "Their function may have to do with social life, and enforcement of rules and giving a narrative to them, which is what religions really do."
from "The Beginnings of Morality lie in Primate Behaviour." Frans de Waal.
New York Times. March 2007.