Well, I came out as both gay and atheist at the same time... kind of a double whammy. My parents were a lot more concerned about my being gay. However, since i also said I didn't believe in god, they had no religious arguments to use, and that just emptied their arsenal.

I lost a few friends when they found out. They proceed to call me names and were very dramatic about it. As far as my parents go, we never really officially talked about it. I would make comments as a kid every now and then along the line of “he’s your god not mine” and I think they finally just figured it out. Most of the people I know are ok with it.