Dabbleboard is an incredibly cool application, that can be used as a whiteboard. In fact, it is a whiteboard, but it can be used for drawing Mindmaps, Flowcharts, diagrams or for marking up pictures.
Dabbleboard is a powerful online whiteboard that’s actually easy and fun to use. With a revolutionary new interface, Dabbleboard gets out of your way and just lets you draw.
Draw with flexible tools. Reuse previously-made drawings. Share and collaborate in real-time. All as naturally as using a marker or a pencil.
For teachers this is great, but it works for presentations anyway. Itg will even work better with your favorite slide application (Power Point, OpenOffice Impress or SlideRocket).
Kuehleborn's World 