This paper reports the results of a 2-year study investigating the types of experiences and support necessary for in-service teachers to effectively integrate Geographic Information Systems (GIS) in their teaching/learning environments. The complex nature of GIS software prompted the authors to ask whether GIS can be a useful tool in the classroom. In an effort to answer this question, workshops were conducted, assessed, and revised in an iterative process. Assessment measures included classroom observations, interviews, participation in Web-based discussions, and lesson plan analyses. Results include documentation and rationale for the evolution from an intensive multi-day workshop with follow-up classroom support to a three-part series of workshops distributed over a 6-month period with classroom support available. Qualitative analyses include excerpts from classroom observations, interviews, and lesson plans which contrast the level and type of use by teachers who participated in the in-services. Many of the 15 participants in the first workshop did not successfully integrate GIS into their classrooms settings. The large majority of participants in the last workshop were able to plan and implement lessons incorporating GIS in meaningful contexts. GIS is a tool that is being used extensively by researchers, scientists, and planners. Until recently it was not feasible for educators to use this spatial data resource because the cost of the software was prohibitive and the size of the data files was too large to load on the personal computers used in most school settings. Demand from public and private sectors, coupled with spiraling innovations in technology, have resulted in the recent introduction of software which can be used to manipulate spatial data on personal computers. Software companies such as Environmental Systems Research Institute, Inc. (ESRI) have produced software bundles for school systems at affordable educational prices. Educators who have had the opportunity to explore these resources are excited about the potential of these spatial data resources to enhance the achievement and conceptual understanding of students in content areas including geography, science, mathematics, art, and technology. Students can investigate real-world problems to understand concepts and patterns about such topics as climate, human usage patterns, and the earth as a system. These same patterns can serve as inspiration for art projects, and the software tools can allow multiple perspectives. Students can also take on the role of planners by querying the spatial data to help manage crop production, range management, county, and city planning. The purpose of this study is to develop effective professional development workshops in the use of GIS. This includes the support and information necessary for interested Wyoming teachers to use these resources in their classrooms to increase and enhance student achievement in areas of art, science, mathematics, geography, and technology. (Author/YDS)