Crystallography
http://icsd.fiz-karlsruhe.de/icsd/
http://www.iucr.org
http://img.chem.ucl.ac.uk/sgp/
X-ray Physics
http://physics.nist.gov/PhysRefData/FFast/html/form.html
http://xdb.lbl.gov/
http://www.cxro.lbl.gov/
http://www.x-ray-optics.de/
Synchrotrons
http://www.esrf.eu
http://www.anka.kit.edu/english/28.php
University
http://www.physnet.uni-hamburg.de/institute/IAP/angew.html
Software
http://www.esrf.eu/computing/scientific/xop2.1/intro.html
http://www.esrf.eu/computing/scientific/joint_projects/ANA-ROD/
National Societies
http://www.dpg-physik.de
http://www.dgm.de