I've just heard about this and want to learn more - any suggestions for books, videos, clinics?

yep buy a halter.

no im sorry i had to say that. Actually theres a certain point when youve neckreined lightly enough and if you use voice commands and leg commands all the time i dont feel like explaining it right now, but it gets too a point where you can drop the reins and just use your legs. It takes a few months of riding, lots of patience and mostly there arent really books on it, most trainers try and figure it out for themselves. I know ive seen parelli do it

Check out stacy Westfall. Type her name into a serch eng. and it will come up. She has a great web site and video. She wins big time in freestyle reining bridless. Ausome to watch.

Heidi