Geographic Information Systems (GIS) integrate computer hardware, software, data, and the human mind to bring new perspectives to creative problem solving. The power of GIS is in adding a graphic, spatial dimension to problem solving. Still an emerging technology for most libraries, GIS can be expensive, entails a steep learning curve, and consumes large quantities of computer space. However, strong partisans claim it has already revolutionized the way people look at the world and will solve the world's problems. Most libraries are considering not whether they will offer GIS-based services, but how they will offer them. This report discusses some of the critical choices library planners must make: (1) what kind of service to provide; (2) how to build the collections; (3) staffing the GIS services; (4) learning and educating others about GIS; (5) how and with whom to form partnerships; (6) how and where to store data; and (7) how much it will cost. Based on interviews with 26 information professionals, "Reports from the Field" are presented on GIS-based services at 20 academic and public libraries across the United States. Contact names and information are provided for almost all of the libraries discussed. Future trends in GIS services are identified. (SWC)