I haven't actually read his How to Write a Novel guide. I think, for me, that moment may have passed, but if his blog is anything to go by, it's well worth getting your mitts on.
My publisher, Ghostwoods, put me onto his blog via the entry on blurbs. Since then I've been browsing through, constantly impressed by the helpful and informative tone.
Whether you're interested in writing your first novel, or whether you're an old hand with some specific questions you need answering, Nathan Bransford is a great resource to peruse.