Hi.
I have written a very quick overview of the motion blur system in Blender.
http://mediawiki.blender.org/index.php/Manual/Vector_Blur#Overview
Comments and critiques and technical fixes are more than welcome. Essentially, I spent several hours hunting around trying to find a very simple example of how to make something blurry. It took me just as long to figure out how to actually get something to be blurry. Now even though I tend to be slow in my old age, I felt that was an abashedly long time just to do something trivial like a blurry little sphere.
Enjoy!
T