I would like to start with taking photos at night. Can anybody recommend me a good book or an online resource as a starter?
The elements of shooting in available light, or as I like to call it, available dark:
Learn to hand-hold. With practice you can get 25% of your shots to be usable at 1/4 second shutter speed. Yes that's far beyond the standard rule of thumb but it's easily achievable by learning how to hold your camera steady and practicing constantly. Like playing the piano. You get better by practicing.
Noise reduction in post.
There's more light out there than you think. Street lights, car headlights, neon signs.
Did I mention practice?
More on hand-holding. Here's one article but there are many. http://digital-photography-school.com/how-to-avoid-camera-shake/ The idea is to turn your body into a solid platform for the camera. Then you relax your breathing, concentrate, and when you press the shutter button, apply equal pressure on the opposite side on the bottom of your camera.
You will really be amazed at how slow a shutter speed you can shoot at with confidence, once you master the basics of hand-holding and then practice practice practice.