Here is a good Point of Inquiry interview with John Shook on Naturalism and the Scientific Outlook. There is a good discussion over science and naturalism, and towards the end of the interview he talks about the issue of meaning of life in the naturalist context. Here is John Shook's bio:
John Shook is Vice President for Research and Senior Research Fellow at the Center for Inquiry Transnational in Amherst, N.Y. He received his PhD in philosophy at the University at Buffalo and was a professor of philosophy at Oklahoma State University for six years. Among his current responsibilities are the Center for Inquiry’s Naturalism Research Project and the expansion of the Center’s Jo Ann Boydston Library of American Philosophical Naturalism.