I've got one in the afternoon of march 13th and another on april 3rd. When you all see status change also post your order date and time - so we can get an idea if they're working they're way through by date.
My 64gig-3g just got changed to prepared for shipment two minutes ago. I ordered about 20 minutes into the first day of preorder. I ordered another one about two weeks later, and there is no change on that one.