You can order from Apple or AT&T and both claim that you can receive direct delivery on June 24.
If you want to pick-up at the AT&T store then you have to wait until June 25. Also, as I posted above AT&T had some real issues getting phones delivered on Launch day last year for the iPhone 3GS due to the limited stock they received from Apple and the timing of their deliveries....
Here is the relevant quote from the AT&T announcement:
For greater convenience and faster delivery,
preorders can be shipped directly to a customers home or business for delivery as early as June 24. Customers can also have a
preorder shipped to their local AT&T store for pick up on or after Friday, June 25.
source:
http://www.att.com/gen/press-room?pid=4800&cdvn=news&newsarticleid=30863
Dave