The account information will be given to each user when the event starts (says at the bottom of the thread, May 20th).

And no, you will not be able to go ingame with it. It will, however, be useful to marketeers, as it acts as a holder account for high-qi items.

Sheva: we discussed that, and decided you have to sell the items. That way people won't just stock up on items rather than selling them. It would also be hard to determine an exact worth for the items.