Bamboo DiRT is a tool, service, and collection registry of digital research tools for scholarly use. Developed by Project Bamboo, Bamboo DiRT makes it easy for digital humanists and others conducting digital research to find and compare resources ranging from content management systems to music OCR, statistical analysis packages to mindmapping software.
CmapTools is a free program used by colleges around the world for creating concept maps: graphical tools for organizing and representing our knowledge about a particular issue or system. In CmapTools, concepts (boxes or nouns) are linked together by propositions (lines or verbs) to form a network that visually demonstrates connections between issue components. By creating a visual map of what we know, one can open up new ways of understanding how that system functions and how its components interrelate; this is what distinguishes CmapTools from more traditional (e.g., verbal) modes of thinking and communication.
also check http://cmapskm.ihmc.us/servlet/