The Advanced Accelerator Concepts (AAC) Workshop is a forum for dissemination and exploration of new concepts in the field of advanced accelerators. The 2008 AAC Workshop covered a wide range of advanced accelerator research supporting the development of future colliders and particle and radiation sources. The 2008 AAC Workshop Program was organized into six working groups, addressing the following topics: (1) acceleration by laser-driven plasma-based structures; (2) computational accelerator physics and applications of algorithms to advanced accelerators; (3) advances in technologies for high-gradients using electromagnetic structures; (4) high energy density physics and exotic accelerator schemes; (5) beam-driven plasma-based accelerators; (6) beam and radiation generation, monitoring, and control.