Gliffy is an interesting flash-based online application that lets you create organizational charts, flowcharts, entity-relationship diagrams, and floorplans, and other projects Registration is required, but Gliffy is free with some limitations (you have a limited number of projects that you can work on without signing up for the premium service).
found on Web4Lib listserv (thanks Leo!)
Thanks for the recent mention. We are glad you like it! If you have any suggestion and/or feedback please let us know,
Thanks~ debik(at)Gliffy(dot)com