I believe that my children should make their own decisions regarding religion (when they are old enough to make that informed decision) therefore I don't push my beliefs on them the same as I would not want anyone else pushing their religion on them. When my son asks questions about things I just always say "well some people believe this or that but mommy doesnt believe that". I try to give him the information he asks for without making him feel like I am telling him what to believe.
My question is I guess, do you expect that your child will be atheist as you are? I always cross my fingers that my son will be but I also feel like forcing him to believe what I believe makes me no better than the religions I despise.