This is the presentation that I gave at the FOSS4G 2011 conference.
Relevant links:
http://www.openearth.eu
the tools
http://www.xbeach.org
the XBeach model
http://oss.deltares.nl
the Delft3D model
http://geoserver.org
WCS server
http://geoservices.knmi.nl/adaguc_portal/index.html
Adaguc (WCS server + more)
https://bitbucket.org/SiggyF/html5overlay
the html5 overlays used.
http://opendap.org/
opendap protocol + hyrax opendap server
http://www.unidata.ucar.edu/projects/THREDDS/
thredds opendap server
http://pydap.org/
pydap opendap server