I tried searching Slideshare for presentations relating to health and developing countries. It was difficult to find relevant presentations - I found lots of fundraising presentations. The quality of presentations was variable.
Searching for conference presentations was more successful and I also found some presentations that might be useful for library training. Browsing through the presentations was also useful for getting a feel for good/bad presentation design.
An example of a conference presentation on climate change and health:
I liked Prezi and I found it easier to find presentations suitable for an academic context. I recently saw a good example of it being used at CILIP's Umbrella conference:
http://www.netvibes.com/nedpotter#The_Echo_Chamber
(I couldn't see how to embed this, so assume they have blocked sharing?)