Hi Jay,
It looks like Mozcon used to be called "PRO Training". In previous years, they typically had about 150 seats available. However, I don't see any information online that specifies the number of seats available this year.
Regarding what to expect, check a review that I found:
http://www.bryanphelps.com/2009/08/29/seomoz-pro-training-seminar-review/
Being that I've never attended, I hope that someone will reply with their first-hand experience.