The third web map system for this project is QGIS Server.
This is a very recent development that allows a complete web map, rendered by QGIS server software directly from a QGIS project (*.qgs) file, to be served through a WMS call from the QGIS server.
As of this writing, the project has not yet installed a QGIS server. Once the instructions for installing the server in both Windows and Linux environments have been understood, the software will be installed and QGIS server tested.
From the sparse literature on this product, it can be gleaned that QGIS server is installed by copying the appropriate server files into the FastCGI or the CGI folders of an Apache web server installation. The server files have been distributed with QGIS versions 1.6 onward.
In non-Windows machines, the QGIS server files are placed in the FastCGI folder, while in Windows machines, the files are placed in the CGI folder. It assumes that the Windows machines acting as server does so by running the Apache HTTP (web) server software.
(Attempts at installing QGIS server in a Windows PC for this project have so far been unsuccessful. We hope to have an installation up and running soon...)
It is not clear yet whether machines running the IIS (Windows) web servers will one day be able to run QGIS Server.
The immediate benefit of installing QGIS server would be that no additional work needs to be done to serve a simple but complete web map directly from QGIS desktop.
Another benefit would be that a map created by QGIS desktop could then be served as a basemap image through WMS in an open web map thin client. Data layers from KML or other compatible file formats for the thin client could then be overlaid onto the basemap.
As more information and documentation becomes available in the deployment of QGIS server in Windows and Linux machines, the project anticipates creating open web maps using layers served from QGIS server as well as from the more conventional data files.