I don't know exactly who you contact, but you arrange a party (I think there has to be a minimum, but I don't remember what it is). There is a "per head" price, and that includes these wonderful dessert trays -- eclairs, tarts, creme puffs, chocolatey things, etc., coffee, tea, and hot chocolate. It was indeed the most wonderful hot chocolate -- a big dollop of whip cream all laced with dark chocolate sprinkles. It was a little chilly that night, and it was incredible to sit and watch Illuminations while drinking that wonderful chocolate. It was held on the little pavillion just to the right of Rose N Crown. There were tables and chairs for all of us, and the view was incredible. They let us onto the pavillion at 8:30, so we had time to visit and pig out before the fireworks started. It was definitely worth the per person that we paid, and probably then some. (My DS, age 7, just refers to it as our "sweet party.")
I'll check through my emails about this to see if I can find the original post that described what the party was going to be, how much it cost, and who was in charge. The people who arranged it are here on the DIS (Maddie and Janet, I think), but I will look for the email address, too. (They may still be down in WDW right now. They had just arrived, I think, when we had our party last Friday night (Jan. 3).
Note: Just found this on one of the emails that I had saved about the party. I was wrong about the price. It was a little more expensive than I had thought. It was still worth it.
Cost per person:
22.50 for desserts, beverages, and private viewing location
1.35 for 6% tax
4.50 for 20% gratuity (required by Disney Catering)
1.80 for event guide cast member (required by Disney Catering)
30.15 per person total