According to Gizmodo, at least.
http://gizmodo.com/5563644/iphone-4-preorders-starting-at-400-am-est
http://gizmodo.com/5563644/iphone-4-preorders-starting-at-400-am-est
AT&T told me midnight PST, so who's to say who's right?
Gizmodo could say the sky was blue and i'd question the legitimacy of their statement. I'll trust the national enquirer on apple news before gizmo.