Re: Lefty Kreh is the man!
Lefty lives a few miles north of us. I met him briefly at an Trout Unlimited meeting and later arranged for a short fly casting session for my wife and myself. The one hour session stretched into two. Both of us learned a great deal and really improved our casting under his tutelage. Lefty is an extraordinarily patient teacher and a gracious man. As Bigjim said above, he has a great sense of humor! If you ever have the opportunity for a private or small group session where he can carefully watch what you do, do it...it's well worth it.
BTW, Lefty has a number of fly casting apps available from I-tunes... some are free, one is very inexpensive. All are great resources.