Just as the city of Charlotte, N.C., gears up to host the Democratic National Convention, an atheist group is mounting a billboard campaign attacking the religious faiths of President Obama and GOP challenger Mitt Romney. The signs, paid for by American Atheists Incorporated (AAI) and appearing along keylocal highways, include messages such as: "Christianity: Sadistic God, Useless Savior" and "Mormonism: Magic Underwear, Baptizes Dead People, Big Money, Big Bigotry." AAI President David Silverman told FoxNews.com the signs are aimed at keeping religion and politics separate as the convention gets under way Sept. 3. Other faiths, including Judaism and Islam, were...