I just realised that I should announce my new book in this forum. Details are Freedom of Religion and the Secular State (Wiley-Blackwell, 2012). If you can't afford it, maybe your local or university library can! :)
http://www.amazon.com/Freedom-Religion-Secular-Blackwell-Philosophy... (paperback US, as linked above)
As you'll see, AC Grayling writes: "This is a must–read: Blackford has given us a forceful and persuasive book that will have a big impact on the debate it addresses."