Operabob,
I agree that most videos are excellent resources to study movement. I watch them over and over again myself, and have picked up choreography ideas from the Andy/Wendy Wong Grand Ballroom videos you mentioned. However, my impression is that the original poster is a newer dancer and wants to learn the Cha Cha, and as such I didn't think this particular set of videos would be as helpful as others I have seen that DO discuss basic technique, lead/follow, etc.
whoops, didn't mean for this to be anonymous like the last one. Thought I was logged in....