GIS (Geographical Information Systems) is of course about making maps - but it's also about spatial analysis, spatial queries, spatial statistics...
For example, we might want a map showing all the hospitals in a region, but also a tabular report showing the nearest hospital to each major settlement. Sometimes data is more useful (and more interoperable) than a map.
QGIS is an open source, freely downloadable and distributable desktop GIS package. It has an active developer and user community, and is widely used in the humanitarian world. It's robust, well-supported (including by many commercial organisations), and integrates extremely well with other open source tools such as PostGreSQL/PostGIS and GeoServer. It uses as components other open source libraries such as OGR and GDAL, enabling it to handle all standard GIS formats such as shapefile, KML and MapInfo TAB file, as well as many less well-used ones.
Although it's free to use, QGIS relies on users and sponsors to support its development if they can - we'll look at this at the end of the workshop.
There are alternative open source GIS desktop packages - gvSIG (widely used in Spanish-speaking communities) and uDIG to name only two. See http://www.osgeo.org/ for more information about open source in GIS.