I was listening to the latest .Net Rocks! podcast and one of their guests mentioned some posts about public speaking on Josh Holmes's weblog. I decided that I was interested in reading them so I slapped his blog URL into Firefox.
I didn't find the posts i was in search of, however I did stumble across a post which told me about a great video explaining Twitter. It's fantastic! It's all done using animation and paper and it's all "in plain English". The best thing about these videos (apart from the fact I found them entertaining) was that despite it being something I think my Mum would be able to understand there were none of the factual errors which seem to plague most "plain English" descriptions of technology.