For what it's worth I spoke to a upper level supervisor today that told me not to pay any attention to the back order status and if you ordered early on the 15th then you should be all set for a phone on the 24th.
He confirmed to me that the phones ship out the 23rd to arrive on the 24th.
I ordered through Premier on the 15th at 5:40 a.m I received an email, my card was charged and my date says the 15th.
Many people are being told the phone ships on the 24th, that is not accurate, it ships the 23rd if you pre-ordered early.
These will be staged at FedEx or UPS, and they will be shipped on behalf of either Apple or ATT. It isn't like these are at an ATT warehouse, they are all together and shipping from teh same place as Apple orders. I think you are OK to get your iP4 ON the 24th... if you don't get backordered.