There's a thread about this over on Richard Dawkins' site - it's not a terribly long one, but some comments made there led to me making a long comment, which has produced a few additional responses.
One of the issues that received a fair bit of discussion was how practical it is writing philosophical books, and what practical steps should be taken to advance the cause of secular government. In particular, someone asked whether Freedom of Religion and the Secular State contains advice about how secularists should organise.
Answer - it doesn't. It's not that sort of book, and you'll be disappointed if you buy it expecting that. It's a philosophical book, which means that it tries to deal with its subject matter rigorously and honestly. I changed my mind about various things as I was researching and writing it, and if I'd changed my mind about even more things then the book would have reflected that.
I think it's valuable for all sorts of reasons to investigate concepts such as freedom of religion and phenomena such what happens when religion interacts with political power. We should try to get these concepts and phenomena clear, and there didn't seem to be another book that did precisely the job I wanted (the closest may be Martha Nussbaum's Liberty of Conscience and Ahdar and Leigh's Religious Freedom in the Liberal State - both of which contain much that I disagree with). While I always knew that I was going to be advocating and celebrating a form of secularism, I didn't know until quite a late stage exactly how I would be conceiving of it. That's the nature of doing honest philosophy.
So this sort of exercise seems to me to be valuable for reasons that go far beyond advocacy of a particular cause or set of causes. The book might have turned out to be an embarrassment to some people whom I generally regard as allies, though as it turns out that probably hasn't happened (I can't think of much that should embarrass the people I'm thinking of).
As its turned out, Freedom of Religion and the Secular State could probably be endorsed almost entirely by organisations like the CFI. Any disagreements would be on relatively fine points. But there was no guarantee of this. Given the line that I defend, the book will be a valuable resource for people involved in advocating secularism in, say, the US. Indeed, it will be of more immediate use to them than, say, Nussbaum's book, which is quite pro-religious, whereas Freedom of Religion and the Secular State is about as neutral as it's possible to be on the subject of the truth and value of religion.
If I were deliberately setting out to offer advice on organisation of the secularist movement, I'd think of quite a few things to say, some of which have been said by others in the past. For example, I'd say, as others have said, that there are pragmatic reasons, as well as principled reasons, for secularists to defend freedom of speech - and when we do so, that should include defending the free speech of our opponents. There are doubtless many other practical points like this, and I think that conferences, panels, and seminars are good places to discuss them. There's no reason why they couldn't also be discussed in books, but we should, I think, go on thrashing out these sorts of issues face to face, in real time, whenever we can.