There are different ways to pre-order.
You can pre-order it through the AT&T site, they will send it to your house ( maybe your work too ) OR send it to a local AT&T store, where you can pick it up. If you send it to the AT&T store, you can only pick it up as of the 25th, not the 24th ( this was mentioned somewhere, must have been the keynote ).
If you order through the Apple store, you can have it delivered and it will arrive on the 24th, OR you can have it sent to a local Apple store where you can pick it up, also on the 24th.
*Edit: Note, post count means nothing. I could be wrong, it's happened to me once or twice