If you've ever been curious about the philosophy of atheism, then here is a link to a page of reviews of books about atheism. Of the books listed, I've read Freethinkers (which actually is about secularism and not atheism), Atheism: The Case Against God, and a good bit of H.L. Mencken on Religion. The first is about America's rich history of secularism, the second is straight forward (non vitriolic and non polemical) logical examination of whether or not belief in God is rational, and the third is a just plain interesting compiliation of American iconoclast journalist H.L. Mencken's writings on religion (as if you couldn't tell from the title), particularly so in Mencken's coverage of the Scope's trial. On the list I also see Michael Martin's Atheism: A Philosophical Justification which I've skimmed and can say provides a comprehensive examination of the arguments for and against the existence of God. Of the four, Freethinkers is the most entertaining, and perhaps most socially relevant.
Another interesting site, at least to me, is BookTalk, an online book club discussion forum. Discussions tend to be about books of popular science and secularism. A neat feature of the site is that they invite the author of whatever book they are reading for a live chat. Previous chat participants include two of my favorite authors: Michael Shermer and A.C. Grayling. If you've ever wanted to have someone to bounce ideas about a book off of, then this is the site for you.