The quality of information is crucial for decision making in many mission-critical applications such as battlefield operations and intelligence analysis. However, as the system becomes larger and more diverse, it is becoming increasingly difficult to assess the quality of information from various operators or data sources. In this paper we propose an agent-based approach to managing the quality of information, e.g., its trustworthiness, in network centric information sharing environments, where software agents collaborate with each other to automatically represent and assess the trustworthiness of information from its pedigree within the framework of Dempster-Shafer theory.