Have just finished watching Kreiger's "Essence of Spey Casting," and wondering why he bothered? Not real impressed, but it was a good review of the basics...
I have seen Vincent's "Introduction to Double-Handed Rods," and "International Spey Casting." Thought they were both excellent. Also really enjoyed John and Amy Hazel's "Introduction to Spey Casting," although I did get a bit of a headache after that one.
Any suggestions? Just trying to learn the Single and Double Spey right now....not sure how much of a strategy that is, but it is fun and I even pretend like I am fishing while I practice the casts in the river.