This paper presents a description of and design considerations for silicon/PLZT spatial light modulators (Si/PLZT SLMs), which provide high parallel processing power, dynamic range, cellular resolution, sensitivity, and the potential for implementation of "smart" optical devices. Following an overview of Si/PLZT SLMs, we discuss potential performance with respect to fundamental limits. We then review the current technology related to the development of these devices to meet the highest performance goals. Finally, we predict performance in specific applications. This analysis suggests that Si/PLZT SLMs can play an important role in the implementation of a variety of optical processing and computing systems.