POV-Ray Page:

The Persistence of Vision Ray-Tracer creates three-dimensional, photo-realistic images using a rendering technique called ray-tracing. It reads in a text file containing information describing the objects and lighting in a scene and generates an image of that scene from the view point of a camera also described in the text file. Ray-tracing is not a fast process by any means, but it produces very high quality images with realistic reflections, shading, perspective and other effects.

The best bit about POV-Ray is that it is distributed as freeware, and can be downloaded from www.povray.org. This is not a cut down, or demo version, it is the complete package.