A beta of the iPhone SDK was released this afternoon at about 1 CST. I immediately tried to get on the site, only to be greeted by a friendly page that said:
Safari can’t open the page “http://developer.apple.com/iphone/program/” because the server unexpectedly dropped the connection, which sometimes occurs when the server is busy. You might be able to open the page later.
This continued all afternoon until just about 10 minutes, when I was finally able to get through!