My favorite book on night photography is called Night Photography by Andrew Sanderson. While it's old enough to be focused entirely on film techniques, he does a great job talking about some of the considerations. And the black & white photos of English towns in snow are just great. There's also a new book out which I haven't seen that is dedicated to night photography with digital cameras. Check out Night and Low Light Photography, Professional Techniques from Experts for Artistic and Commercial Success by Jill Waterman.