To buy a ticket, you must be a member of the iOS Developer Program, iOS Developer Enterprise Program, or the Mac Developer Program as of the announcement of WWDC (5:30 a.m. PDT, April 24, 2013) and at the time of your ticket purchase. Developers between 13 and 17 years of age must have their ticket purchased by their parent or guardian who is an eligible member.
Ticket purchases are limited to one (1) per person and five (5) per organization. The same credit card may be used up to five (5) times to purchase all of the tickets for your organization. However, each team member must sign in with their own Apple ID and purchase their own ticket.
So now we can set our calendars and stop taking our iPhones to bed.