The development of net-centric approaches for intelligence and national security applications has become a major concern in many areas such as defense, intelligence and national and international law enforcement agencies. In this volume we consider the web architectures and recent developments that make n- centric approaches for intelligence and national security possible. These include developments in information integration and recent advances in web services including the concept of the semantic web. Discovery, analysis and management of web-available data pose a number of interesting challenges for research in w- based management systems. Intelligent agents and data mining are some of the techniques that can be employed. A number of specific systems that are net-centric based in various areas of military applications, intelligence and law enforcement are presented that utilize one or more of such techniques The opening chapter overviews the concepts related to ontologies which now form much of the basis of the possibility of sharing of information in the Semantic Web. In the next chapter an overview of Web Services and examples of the use of Web Services for net-centric operations as applied to meteorological and oceanographic (MetOc) data is presented and issues related to the Navy's use of MetOc Web Services are discussed. The third chapter focuses on metadata as conceived to support the concepts of a service-oriented architecture and, in particular, as it relates to the DoD Net-Centric Data Strategy and the NCES core services.