If you call Disney Group Reservations in the Grand Floridian, they will send you an Alpha listing via email or FAX, so that you can keep up-to-date. We don' thave access to a home FAX, but they were always very good about sending the emails.
As for spreading the word, we spoke with a number of our guests beforehand. We let Disney send out the planning packages and then we sent out a newsletter about 4 pages long (2 pages front and back) with information regarding weather, hotels, must see attractions, etc. We established an email account for the wedding itself and asked people to send us their reservation information for guft baskets and to keep an eye on the Alpha listings. We had a lot of military staying at Shades of Green, whcih didn't count, and a lot of military overflow into the main resorts, which I believe did count... I can't remember NOT seeing the names on the Alpha listing.
SOG was the only one that didn't deliver the gift baskets though. We got a call 3 weeks after the fact asking what they should do with it... eat it, duh.