'Slideshare' , http://slideshare.net/, is a great way to upload PowerPoint presentations. I made this one for a TAFE SA workshop in November 2006. As it seems the inserted audio file does not work, I am adding the Martin Luther King mp3 file I used that I found at http://blog.lextext.com/blog/_archives/2006/1/15/1676937.html, thanks to Wikipedia.
