A great site to look at first if you are looking for presentations is Slideshare. From around the world various people have put up their presentations from the sublime to out of the box.
Various people have asked for copies of the presentations that I have made over the years and I have set up my own slideshare account for others to access.
Overview of education and enterprise in Scotland
Creativity
Comparison of entrepreneurship in Norway and Ireland (Dr TM Cooney & Dr Beate Rotefoss)