Anandtech has a great article detailing the proper way to set up your digital camera to capture various images at night. Everything from evening portraits to capturing motion is covered here.
One of the best pieces of advice is just plain common sense, and that is to get a tripod to help stabilize the camera for the long exposure times.
Aside from that, the tips on ISO and Shutter settings are excellent bits of information that will help your night photography look great.
Via Lifehacker
Wow, I agree, great stuff.
If you have a tripod and take night pictures in slow shutter speed, it’ll solve 90% of the problems. But most of the dark shots I take are indoors (bars, clubs, etc), and spontaneous: No tripod, regular shutter speed, and no flash. Heavy photoshop work is the only solution for me.
reply to #3:
another solution to shooting in dark areas with no tripod is to buy a vibration reducing lens (the lens elements actually move to help balance out the movement of the camera). Handheld shots can be sharp down to 1/4sec shutter speed, when normally you cant hand-hold below 1/60.