Here's a site that proceeds to give a layman's explanation of the ten dimensions. I thought it was entertaining and thought provoking, but I wanted to see what people that have a better idea about these thing felt about it. (I hope this is in the correct topic area.)
To view the animated version of the explanation, you will need Flash installed. There is a text version there too.
Here's the site: http://www.tenthdimension.com/