Also, starting on September 18, 2006, eligible participants can enter without being present in a Disney Property by writing their full name, complete mailing address (including postal code), daytime telephone number (including area code), and date of birth on a 3.5"x5" postcard and sending it with proper postage affixed to: (i) if a legal resident of the United States, District of Columbia, Puerto Rico, Canada or Mexico: P.O. Box 8629, Elmhurst, IL 60126; or (ii) if a legal resident of the United Kingdom: Disney Dream Giveaway, 483 Green Lanes, London N13 4BS. Participants may enter once per day during the Giveaway Period. All mail-in entries must be mailed separately, postmarked by December 31, 2007 and received by January 14, 2008 or they will be void.
These are the rules from the disney site. You can send in a postcard for every member of your family once a day (including children). I would use the prepaid postcards from the post office. The do the drawing on the 20th of each month. From there if you have won anything it will take 45-55 days to recieve your prize. I sent mine in April and won something the first of June. There is a sticky on here that will give you all the information that you need.