Atheists can be moral if they behave morally, just like anyone else. If there can be such a thing as an immoral believer, there can be such a thing as a moral atheist.
Sure they can. Even if you get past Gustaf's point about free will (which I believe is a good one), I'm sure anyone can adhere to a set moral standard. The real question is what does an atheist believe to be moral? It is why, in my opinion, politicians running as independents have an inherent disadvantage. Voters notice an R or D by a candidate's name and have some idea of what the candidate stands for even if they know nothing more about them, but an "I" by the name is a blank slate. An independent could be an anarchist, communinst, facist, libertarian, or something in between. Certainly an independent can be as Republican as any other Republican or Democratic as any Democrat, but since they give no hint of their beliefs in their party affiliation, the average voter may have no clue what to expect. Similarly, an atheist could act within the moral precepts of Roman Catholicism as well as the average Catholic or adhere more strictly to the tenants of Sunni Islam than the average Sunni Muslim. However saying you're an atheist does not convey any sense of what you hold to be moral. If you wish to convey to what system of morality you hold, describe yourself as an Objectivist, Utilitarian, Christian Atheist, Hedonist, Nihilist, etc, this says volumes more about your moral convictions that simply saying "I'm a moral Atheist."
