Slideshow presentation creation and hosting tools
SlideShare ~ share your presentations, documents and videos. Presentations can be linked at the site itself or embedded in a web page, and also a tremendous resource site of presentations. SlideShare supports documents, PDFs, videos and webinars.
Prezi ~ will create a map of your ideas, images, videos, and show an overview with all the details.
VoiceThread ~ helps you create collaborative presentations.
Second Life ~ create an avatar and explore this second world for learning, gaming and training. SecondLife is a virtual, 3D imaginative and animated world.