Yeah, so are we. We have no idea when exactly "today" it will be released -- Apple can pull the trigger whenever they want, first thing in the morning New York time, or last minute at night in Cupertino. So, all we can do is wait and keep hitting that download button.
Or, if you want to help pass the time, check out TiPb's iPhone Forums. They're friendly, informative, and fast and free to join (for those few who haven't already).
There's even an official "Staying up for iPhone 3.0" thread, courtesy of Tremain, to get you started!