If you are interested in software for Bayesian nets, I enthusiastically recommend that you read K. Murphy’s excellent 3 page review article entitled “Software for Graphical Models – A Review” (ISBA Bulletin, Dec 2007).
By the way, the website of Prof. K. Murphy (Uni. of British Columbia) is also well worth a visit. I found the class notes for his courses on B nets and related topics very clear and helpful. Prof. Murphy is the author of a popular B net software package (in MatLab/C) called Bayes Net Toolbox (BNT). For many years, he has kept an authoritative table comparing various B net computer programs.