It should come as no surprise that MMS is sold out. See the Microsoft note here about ways to still register.
http://www.mms-2010.com/public/registrationoverview.aspx
It will be a packed croud. I think my first time has close to 4,000 participants. Even with the large venue like the Venitian it can be cramped between sessions. I have been practicing my session. Let's hope it lives up to everything. With 3 kids, a bad car wreck, medication and just everything else happening I hope it comes out well.