i ordered the 8gb yesterday with next day shipping and it said it would be delivered the 10th. today i changed my mind, cancelled the order and ordered the 32gb with next day shipping and now it says it will be delivered the 13th. WTF!
For one, the 8GB are in less demand than the 32GB. In the first 24 hours I'm sure they racked up quite a list of pre-orders for the 32GB, and now you're much further from the top of the list, knocking your order back a few days.
Maybe you'll get a surprise and it'll come sooner.
I don't know if this information helps or hurts, but a few minutes after the Apple Online Store came back online yesterday, I ordered and 8GB and a 32GB, and both are due to arrive on the 10th-14th with free shipping. So it always pays to get in on it early.