Recently MapWindow GIS completed one year to be released as open source software. The MapWindow GIS 4.0 desktop application now supports over 3,000 projections, is now international and also checks the status of the language. It includes GIS tools for raster and vector projection, clipping, and merging, supports GeoTIFF and several additional file formats, loads faster and is more stable than version 3.0 and includes a VB.NET/C# scripting interface for writing scripts. It can be extended with plug-ins written in any .NET language and is rapidly being adopted by many agencies and universities as a platform for distributing data, models and research tools. The MapWinGIS ActiveX control now runs in Microsoft Access, Excel, PowerPoint, Delphi, and any platform that supports COM. It includes the GDAL open source libraries for a variety of file formats, the PROJ4 library for projections and the GPC polygon clipping library. It is faster and more stable, is available in a streamlined open source installer that can be included with your software and is free to download, use, and redistribute. At www.MapWindow.org one can download MapWindow and plug-ins, post questions on an active discussion forum, view and contribute to source code, read and add to the WIKI-based documentation, join the MapWindow Developer Team and subscribe to and from dynamic lists to track code, bugs, and discussions.