Jeff,
Haven't messed with throwing knives since I was a kid, but lately the thought to give it a try has occasionally crossed my mind. Just to see what happens. I'm sure if you go to one of the Martial Arts type sites you can find some info; however there is a supposedly good video called Recreational Knife Throwing by John Bailey(who's been at it for 40 years) available from Texas Knifemakers Supply for $19.95.
Sheffields offers Blackie Collins book "Knife Throwing-Sport,Survival,Defense" for $39.00, also "The Art of throwing Weapons-What's Available" by James W. Madden. I reckon any of these should be of help; well, the first two mentioned especially.
