Watch "Creating Motion" Video at Ultimate PhotoGuide
video.ultimatephotoguide.com/video/Creating-Motion
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Layne Kennedy demonstrates the technique of capturing motion in your photos by panning with a fall leaf and utilizing proper fall light. An Ultimate PhotoGuide (UPG) original video.