SlideShare

Slideshare http://www.slideshare.net/ offers you a way to post your presentations (PowerPoint, PDF, and OpenOffice) - up to 30MB - and share them with the world. Of course, I don't care about sharing with the world, but there are times I want to share my presentations with more than a couple others and this is a great repository for you to use to do just that. Think of it as free web space for hosting your presentations.

It is also a cool place to find presentations on topics you are interested in teaching or learning - (i.e. Teaching Excel or Animals and Disaster). Once you find a presentation in your area, you've also found someone who knows about the topic you are interested. You can see other presentations from that same individual.