WEBWEAVR-III is a Java application that supports the construction of Bayesian networks, inference in standard and dynamic Bayesian networks and decomposable Markov networks, construction and verification of multiply-sectioned Bayesian networks (MSBNs)...
Very generic and free (LGPL) Belief Network Framework in C++ - supports a broad range of knowledge and dependency types for network variables and clusters of variables
BNetT.Builder is a desktop application for rapidly creating Belief Networks, entering information, and getting results. BNet.EngineKit is a developer toolkit for researchers and engineers to use to embed belief networks in software applications.
Bayesian network, simulation and risk analysis software. Supports exact and approximate inference in hybrid and dynamic networks for decision support, diagnosis, statistical learning and prediction applications.