I had a go at Prezi today – www.prezi.com. It takes a little getting used to but it is a nice alternative to powerpoint. Just like powerpoint you can spend more time messing about with the various settings changing the way things look on your presentation. So take my advice and remember that your target is to get the information across, not have it flash across the screen in bright colours and flashing lights.
Have a look at this prezi video to get yourself started