The launch of the new Apple iPhone 3G S will be different than for the previous two iPhone models. Right after the announcement at the WWDC 2009 you can already pre-order a new iPhone 3G S at the Apple store and a bit later on AT&T.
BGR reports that their sources tell them that the initial batch of iPhone 3G S at AT&T is already sold out. If you have not already pre-ordered you would have to wait 1-2 weeks longer for the new iPhone 3G S.
The Apple Store still says that you get the iPhone 3G S on June 19th if you pre-order now.