Both conventional cameras and digital cameras have capability to successfully capture images in the dark. And night photography, as a technique, can yield some amazing looking shots for a photography portfolio.
To achieve a good night photograph when using a conventional camera, always use a tripod - and don't use a flash. The effect of showing that the picture was taken at night is attained through a long exposure process - not the lighting of the image. The shutter of the camera should be left open for a certain amount of time to correctly capture an image at night. A conventional camera should have a setting for an open speed or bulb setting - which means that for as long as the button on the camera is depressed, the shutter remains open and the image is being captured. This process allows whatever light is present to penetrate the camera and capture the image on film.
Artificial light is a big factor in night photography - and the presence of it can ruin a great shot. There are filters that are readily available to offset colors from artificial light that might appear on your film. Even the slightest presence of street lights and other outside lights - also known as tungsten lighting - can leave a greenish glow on your shot. Inside lights shining on to your object can give your image a yellow look. If you're planning on engaging in nighttime photography, it's important to have the different filters you might need for your conventional camera, so you can prevent unwanted coloring effects.
Most digital cameras have a built-in "white balance" control setting. In order to achieve a night photograph, you'll probably have to override that setting. Pricier digital cameras will probably have an automatic adjustment, so if you point the camera to an object, the setting will automatically adjust to the setting it needs to take a good shot. Again, you'll probably have to override it to achieve a nighttime photograph.
As long as you understand the need to override automatic settings in a digital camera, you can achieve a night photograph on a digital camera very similarly to the way you achieve one with a conventional SLR film camera: through an extended opening of the shutter speed. One thing you probably won't need with a digital camera is a tripod. Digital cameras are, by nature, far more steady than traditional camera.
One thing you will notice on digital cameras in night photography is the tendency for images to appear grainy or "noisy". This can be attributed to the lack of pixels that comes from the lack of color during the actual photographing process. Luckily, many digital cameras, especially higher-end models, have a noise reduction function on the settings.