I've done classes with Raven and Kaiser and some at home with Holly and attended a 5 day camp last labor day. It's a ton of fun. Low pressure sport that dogs really love.
A lot of instructors have their own way of teaching it. Some go slow, some go fast.
Raven (GSD) - December 8, 2007
Kaiser (GSD) - November 2009
Holly (GSD) - March 24, 2011
Best Paw Forward