With the exception of the Apple Store in Tigard, OR and one in Pittsburgh, PA, Apple Retail is sold out of the iPhone nationwide for July 5th, 2007 -- according to Apple's iPhone availability tool.
While the July 4th holiday may have delayed shipments today, in-store availability has steadily been declining since the iPhone launch.
Apple's online store continues to cite 2-4 week delays in online orders, but some early iPhone orders are said to be shipping this Friday, July 6th.
Of interest, WaitingforiPhone claims they have heard that AT&T has fulfilled over 1 million iPhone activations since its launch. This remains unconfirmed, but we would expect Apple to make some sort of announcement shortly if true.