Now, you're wondering how you can take part in this amazing event. Send your name as it appears on a photo ID, your name on the official forums, your age (you must be over 18 to attend), and which session you would like to attend (7 p.m. or 9 p.m. GMT) to firstname.lastname@example.org. The event is invite-only; if you get in, you will receive an invite by March 31st. Be sure to include every piece of information BioWare asked for or you will not be eligible for an invite.
All the origin worlds and classes will be open for play at this event, and spots are first come, first serve. Hyperdrive over to the official forums now for more information!
[Update: According to Senior CM Stephen Reid, "tickets were gone about 40 minutes before you posted that story."]