Too many words, too many animations, reading the slides word for word, bar-graph overload, bad colours, no real content.... Jamie McKenzie has a great (even if it was written in 2000) article on avoiding Powerpointlessness. He includes many tips from planning to presenting, and assessing. Worth a read.
There's actually a funny clip that illustrates the bad techniques some designers use. Click below for the video.
Life After Death by PowerPoint
There are a number of on-line tutorials that teachers can consult to help students create an effective presentation. The important thing to remember is that the slide show simply highlights the points that the presenter is making: main points & key graphics, not pages of text!
One way to have students present PPT and also make them available for the rest of the class to review later is to use a site like Slideshare. With this Web-app, students (and teachers) can upload short Powerpoint files, and then play them on any web-connected computer. While it doesn't support fancy transitions and dancing graphics, it's also a good way to archive student work. It will also allow you to add audio.
Another way to upload your Powerpoint with audio is to use "Authorstream" - it's a quick registration (And it's free.) Click here for the instructions.
And if you want templates galore to try, check out "Indezine".
