I'm not sure that it is going to start.
The point of a beta is to get feedback on things and change the game on release, but the game is going to be on store shelves on July 2, and there's other preparation that needs to be done as well - pressing the discs, making the boxes, shipping things, so it has to be locked down earlier than that. Not to mention assorted other bugfixes and last minute tweaks.
So really, how much time could there possibly be for a semi-open beta?