The Galaxy S announcement was in New York as well. They announced for Verizon, AT&T, and Sprint. The first one hit two weeks later.
This one was originally scheduled for May 26th but was canceled at the last minute.
The Verizon roadmap last week said that Verizon would get it on Sept 8. We have heard the same date for Sprint and AT&T. Samsung needs to be in the US before the iPhone 5.