From the WoW's main page:
- To be eligible for the BlizzCon ticket drawing, you must (1) have an active Blizzard Account that was created on or before 9:00 p.m. PDT on Tuesday, August 12, 2008, when we first announced BlizzCon 2008 tickets had sold out; (2) be an adult in your country of residence; (3) have not previously purchased BlizzCon 2008 tickets; and (4) live in the United States, Canada, Australia, New Zealand, Singapore, France, the United Kingdom, Germany, Austria, Denmark, the Netherlands, or South Korea.
The opt-in period begins on Wednesday morning and will end the evening of Sunday, August 24. As this is a random drawing, those who opt in early will not have a better chance of being selected than those who opt in later.
- After the opt-in period ends, we will randomly select 1,500 eligible Blizzard Accounts from the opt-in pool to receive the opportunity to purchase up to two BlizzCon 2008 tickets. If selected, you will be notified via email with further information about how to purchase the tickets.