This article describes the work of Project ImpactCS, which was initiated to define the core content and pedagogical objectives for integrating social impact and ethics into the computer science (CS) curriculum. Over a three year period the project will address three major problems that hamper the implementation of across-the-board curriculum change: the lack of a well-specified definition of what the core content and learning objectives should include, the lack of a strategy for adapting and adopting existing materials that address the core topics into the existing CS curriculum, and the lack of awareness and expertise on the part of most CS faculties regarding the need and methodology for presenting such material in their courses. This report provides the conceptual frame-work and describes the learning objectives, called knowledge units, for defining a new content area in the computer science curriculum. It also discusses strategies and innovative pedagogical techniques for implementing the knowledge units into the curriculum.