From W3C Wiki
LSW is an open source set of lisp tools for working with OWL and SPARQL using the Pellet reasoner. It was initially written by AlanRuttenberg, but is starting to accumulate contributions from others. A discussion list is at http://groups.google.com/group/lsw-discuss/
Among other things, LSW has treeview based viewer for OWL ontologies based on the prefuse visualization toolkit which shows the fully classified ontology, as determined by Pellet.