OSGeo is an incorporated not-for-profit organization serving as an umbrella organization for the Open Source Geospatial community in general and 16 projects in particular:

Web Mapping: deegree, Mapbender, MapBuilder, MapGuide Open Source, MapServer, OpenLayers

Desktop Applications: GRASS GIS, OSSIM, Quantum GIS, gvSIG

Geospatial Libraries: FDO, GDAL/OGR, GEOS, GeoTools, MetaCRS

Metadata Catalog: GeoNetwork

Other Projects: Public Geospatial Data, Education and Curriculum