I recently took a "Night Owls" night photography class with Aperture Academy, in San Francisco. I've long had an interest with doing long-exposure night photography and have dabbled in it, but this was a good opportunity (courtesy of a gift certificate from my wife) to go a bit deeper. It was a six hour class with a dozen other photographers of various skill levels, touring around to various tourist spots in San Francisco and getting tips on taking good night time shots. I enjoyed the class and would definitely recommend it if you're curious about learning how to do this type of photography.
The photos can also be found at my photography site.