Photographers wishing to make a start in stereoscopic photography are probably well advised to begin by reading the extensive material available on the subject. Those who wish to experiment with the concept without too much commitment might choose to create basic stereoscopic images using a single camera and use them to achieve an initial understanding of the subject. Others might reasonably opt to use digital facilities to capture and mix pairs of images which can then be viewed through special glasses.
However, photographers who are serious about producing good quality stereo images should consider purchasing or creating a specialized stereoscopic camera equipped with two lenses. Ready made film-based and digital products (above and below) are available, but a cheaper alternative may be to join together in an appropriate manner two conventional single-lens cameras. These are then equipped with a common shutter release mechanism which enables the two exposures to be made simultaneously.
An excellent source of detailed information on 3D photography may be found Stereoscopy.com.