Powerbullet Presenter enables you to create impressive, multipage and animated Flash/HTMLpresentations and even includes a few nice little extras you won't get in Powerpoint. In particular, Powerbullet comes with preset animation effects which you can use to animate any object, apply fade-ins, fade-outs, and more. You can also include sounds and voice recordings and it accepts most major graphics file formats.
One especially useful feature is a wizard that helps you create animated bullet lists which gives your presentations an extra touch of class. On the downside, the interface is a bit limited and looks a bit "cheap" compared to Powerpoint but there's no denying that if you're initimidated by the latter, this will have you producing professional looking presentations in minutes.