Decision Sciences Institute
http://www.decisionsciences.org/
"The Decision Sciences Institute is an interdisciplinary, international organization dedicated to the advancement of the science and practice of education and research about business decisions."

Principles of Forcasting
http://hops.wharton.upenn.edu/forecast/
Created in 1997 by Professor J. Scott Armstrong of The Wharton School of the University of Pennsylvania.

Decision Support Systems Resources -- DSSResources.COM, LLC
http://DSSResources.COM/
"The mission of the site is to help people who are interested in learning about how to use information technologies and software to improve decision making. The target audience is IS professionals, IS students, managers interested in MIS and academics in MIS/DSS."

Data Warehousing Information Center
http://www.dwinfocenter.org/
"This site's aim is to help readers learn about data warehousing and decision support systems."

Decision Analysis Society
http://faculty.fuqua.duke.edu/daweb/
hosted by the Fuqua School of Business, Duke University

INFORMS Online
http://www.informs.org/
The online information service of the Institute for Operations Research and the Management Sciences