MapWarper http://mapwarper.net/ is basically the key option for the Wikimaps concept to do the georeferencing. There are others, such as the Georeferencer, http://www.georeferencer.org/, used by the British Library http://www.bl.uk/maps/ project, but the source code is proprietary, though heavily influenced by MapWarper 1. Should the development of the MapWarper be continued?
If one wants to install an open source GIS environment, the way to go is QuantumGIS,
http://www.qgis.org/.
But I am by no means a GIS expert, instead a maps enthusiast.
Best,
Susanna