The Backcountry Bicycle Trails Club, which I'm a proud member, is one of the nation's largest mountain biking clubs and several times a month, the club offers a "Boot Camp" for beginning mountain bikers. Last year alone, for a nominal fee, the club graduated 170 new mountain bikers in the Seattle area.
And with press coverage like this that number is sure to grow. The Seattle Times has a great write-up about the club's educational program, complete with a half-dozen photos. Be sure to check it out -- it sure beats what you're like to find in the paper most other days.