I disagree...because there's more "proof" out there that it may be 8:00 AM...
ATT&T memo that provides information on selling the iPhone at launch day with a reference to 8 AM:
MacDailyNews - AT&T announces Apple iPhone 3G pricing and tips to be iReady 8am local time on Friday, July 11
The question is whether or not Apple with follow the same schedule...
UPDATE:
iPhone 3G Launch Details: Get Those Sleeping Bags Ready