This paper presents an architecture that enables multiple robots to explicitly coordinate actions at multiple levels of abstraction. In particular, we are developing an extension to the traditional three-layered robot architecture that enables robots to interact directly at each layer -- at the behavioral level, the robots can create distributed control loops; at the executive level, they can synchronize task execution; at the planning level, we are investigating the use of market-based techniques for team formation, resource allocation, and role assignment. We illustrate these ideas through applications in multi-robot assembly, multi-robot deployment, and multi-robot mapping.