This will be old news to most but it is new to Edgalaxy.  Slideshare should be considered the youtube of Slide shows.  Where people - and you hopefully can upload your PowerPoints or Keynotes up to slideshare for the whole world see and pillage.  It has tens of thousands of brilliant presentation on a multitude of topics and the best thing is that you can embed them into your own blog (see below) or download and edit them depending if the author has permitted this.  Check it out here - below is an embedded presentation for the uninitiated