I've put together several groups to go to the YES program at both
Disneyland and WDW. It's really pretty easy. Call them and tell them what program(s) you want to do and when. They'll book it for you, send you some paperwork, and give you the date that you have to have your final headcount and payment completed. Collect payment from your group and submit it. Then just show up ON TIME (they wait about 5 minutes past the start time for latecomers then they move on without them).
It's a fantastic program! I went along (adults have to pay also, but depending on the size of your group they have comps for leaders) and learned quite a bit too. Definitely a well organized, well thought out lesson plan.
If you don't have a group of your own, just post on DIS and any other Disney boards/yahoogroups, etc the date and program and tell folks interested to contact you. I can't remember the minimums personally, but I know they were pretty low, so the above post that say 10 or 15 sounds about right. And that count is "paying participants" so if the parents want to go along they count toward the minimum too. When you call and get details be sure to ask about MAXIMUM group number too....I had so much interest in one program and date that we actually split it into two groups.
It takes a little work to organize, but hey, aren't most of us planners anyway? Biggest tip I would give is don't do a committee approach to dates.....because everyone wants something different and that trip was a headache to get organized. The next time I just picked MY preference of a date, posted it and found people who wanted to go on my date....don't know if it was just a lucky pick of a good date, or what I suspect is that folks wanted to do it and made/moved their plans to accomodate it, but it worked much better. Then set drop dead dates for payment to reach you, and if they can't get their act together to get payment to you, take no excuses, just move on...otherwise some people can drag it out and make it a royal pain for you in waiting, writing, waiting some more. This is obviously easier to do if you have more than your minimum....but believe me when I say it's worth dropping folks that can't handle deadlines....'cause I can almost guarantee that they'll be the ones you all are standing around waiting for because they're late....then they get pissed because you left without them and they had to spend 20 minutes trying to find someone to help them find the class, then demand that the teacher start over, which she politely refused, lol. Anyway...that's my horror story and lesson...now I set dates, and get enough folks signed up that the non-payers can just be dumped.
Enjoy the program!