As @carlosdc@carlosdc said, a bayesian network is a type of Graphical Model (i.e., a directed acyclic graph (DAG) whose structure defines a set of conditional independence properties). Hierarchical Bayes Models can also be represented as DAGs; Hierarchical Naive Bayes Classifiers for uncertain data, by Bellazzi et al., provides a good introduction to classification with such models. About hierarchical models, I think many articles can be retrieved by googling with appropriate keywords; for example, I found this one:
C. H. Jackson, N. G. Best and S. Richardson. Bayesian graphical models for regression on multiple data sets with different variables. Biostatistics (2008) 10(2): 335-351.
Michael I. Jordan has a nice tutorial on Graphical Models, with various applications based on the factorial Hidden Markov model in bioinformatics or natural language processing. His book, Learning in Graphical Models (MIT Press, 1998), is also worth reading (there's an application of GMs to structural modeling with BUGS code, pp. 575-598)