Agena is a company which specialises in decision analysis for critical systems, with special emphasis on BN solutions. It markets the AgenaRisk Bayesian network tool.
Hugin Expert A/S - Home Page: Site for the company that produces the Hugin Bayesian net tool
RADAR (Risk Assessment and Decision Analysis Research Group) at Queen Mary & Westfiled College undertakes research in Bayesian net applications to critical systems.
Roadmap to Research on Bayesian Networks and other Decomposable Probabilistic Models . Really extensive set of BBN references hosted by Lonnie Chrisman, School of Computer Science, Pittsburgh
Association for Uncertainty in Artificial Intelligence The main purpose of AUAI is running the annual Conference on Uncertainty in Artificial Intelligence (UAI). Their web site is a very good source or BBN material
Knowledge Industries is a company which specialises in building expert systems based on BBNs. This is a very good web site with examples of BBN applications.
Micrsosoft's Decision Theory & Adaptive Systems Group Extensive BBN acitivity here
BNets -- FAQs & NewsGroups currently contains a small set of FAQ's (hosted by IEI Pisa).
Learning Bayesian Networks This is work done primarily by Wai Lam for his Ph.D. research. It investigates the application of the MDL (Minimum Description Length) principle to the problem of constructing Bayesian Networks from data.
Marco Ramoni's home page research projects and publications Extensive BBN material
Applicability of Genetic Algorithms for Abductive Reasoning in Bayesian Belief Networks
Bayesian Network Interchange Format Home Page
Norsys company that specializes in making BBN tools
Tony O'Hagen's tool University of Nottingham
Bayesian Network Links
Statistical Decision Theory and Uncertainty Reasoning on the Web: Good links here