If you aren’t using SlideShare, you should be. This is a free, easy-to-use tool that helps you share information to a wide audience and more.
With 60 million monthly visitors and 130 million page views, SlideShare is amongst the most visited 200 websites in the world. Besides presentations, SlideShare also supports documents, PDFs, videos and webinars.
Here’s a nice run through the features: http://www.slideshare.net/AmitRanjan/quick-tour
The easy way to use SlideShare is to create an account and post your PowerPoint presentations. Also, you can search the many presentations posted for ideas as you compose your next presentation.