Download the latest version here: http://sourceforge.net/projects/lisem/
List of versions and changes: README
openLISEM runs with the freeware GIS PCRaster
openLISEM is an open source development (GNU GPL v2.0 licence). Using the compiled model or (parts of) its sourcode implies that you are familiar with the details of this licence.
The development of openLISEM is in an opensource environment: the model is made with the QT cross platform application framework and is compiled with VC2010 for windows 32bit. It can be compiled for windows 64bit, Linux and Mac but this is not done (you are welcome to try, Linux seems to work!). For visualization of the graphs and maps it uses the QWT widgets.
The source code of the flood module is based on the opensource FullSWOF2D project of the University of Orleans: website
A manual for the openLISEM software can be found here.