Grid technology enables access and sharing of data and computational resources across administrative domains. Thus, it is important to provide a uniform access and management mechanism couple with finegrain usage policies for enforcing authorization. In this paper, we describe our work on enabling finegrain access control for resource usage and management. We describe the prototype as well as the policy mark-up language that we designed to express fine-grain security policies. We then present our experimental results and discuss our plans for future work.