VUE (Visual Understanding Environment), a free application from Tufts University, might be a useful tool for some people:
The Visual Understanding Environment (VUE) is an Open Source project based at Tufts University. The VUE project is focused on creating flexible tools for managing and integrating digital resources in support of teaching, learning and research. VUE provides a flexible visual environment for structuring, presenting, and sharing digital information.
Much more information at:
vue.tufts.edu