GeoServer - The reference implementation of the Open Geospatial Consortiums WFS and WMS services, GeoServer is...
Sharemap - Sharemap is an online map creation GIS tool.
Mapserver - MapServer is an Open Source platform for publishing spatial data and interactive mapping...
Table & Map - Visualize your location data in an interactive map. Upload an excel or csv file with addresses or latitudes and longitudes to get started.
ESRI Geoportal Server - Esri Geoportal Server is a free, open source product that enables discovery and use of geospatial resources including datasets, rasters & Web services.
QGIS - QGIS is a desktop geographic information system, or GIS.