What kind of pictures at night?
Are you talking stills of cityscapes, etc., using a tripod?
If so, you need to look for a camera with long exposure capability (up to around 15 seconds is nice to have), with a noise reduction system built in to get rid of stuck pixels and noise at longer exposures.
If you mean of moving subjects, that's a different matter entirely. You will not be able to get fast enough shutter speeds, without spending a LOT of money with a Digital Camera. You'll need a camera with a VERY fast lens, capable of shooting at VERY high ISO speeds with low noise.
Some of the review sites, do test a camera's ability to take long exposure photos. You'll see long exposure photos at the reviews at http://www.megapixel.net
to name a couple.
Give us a better idea of what you mean by taking photos at night, and perhaps we can offer more suggestions.