The System Wide Information Management (SWIM) program is a foundational program for the Federal Aviation Administration?s (FAA) Next Generation Air Transportation System (NextGen) initiative, with a goal of providing a common, scalable information management infrastructure. Though some benefits were realized in SWIM Segment 1 from the use of common software infrastructure components (i.e., the Progress FUSE software suite), the actual reuse of service interfaces was limited. The focus of SWIM Segment 2 is increasingly on shared services, with a goal of improved interoperability as well as increased software reuse. This report focuses on shared data access services, based on lessons learned in the SWIM Segment 1 Corridor Integrated Weather System (CIWS) SWIM Implementing Program (SIP) activity, the NextGen Network-Enabled Weather (NNEW) program, and a number of other Laboratory net-centric programs. The applicability of other information sharing architectures, such as the Web and content delivery overlay networks, to SWIM is also assessed. Based on this assessment, a number of recommendations are suggested to facilitate the development of shared services that are flexible enough to respond quickly to evolving NextGen requirements, while at the same time minimizing the overall SWIM software "footprint."