Prezi is a great free online tool for presenting. Teachers and students can sign up for an education account here. Prezi offers a unique way to create and share information and these can embedded in glow.
Prezi also has an app. which means that presentations can be created and shared on mobile devices.
Here are some examples of useful prezis others have made:
The folowing film uses Prezi to discuss the changing face of education and pedagogy for the digital age.