John Gruber has the best take on this:
Someone within Apple leaked the list of URLs to 9to5Mac and MacRumors. I’m nearly certain this wasn’t a mistake, but rather a deliberate malicious act by a rogue Apple employee. Whoever did this is the least popular person in Cupertino. More surprises were spoiled by this leak than any leak in Apple history.
Like Federico Viticci said on Twitter, I don’t begrudge 9to5 Mac for publishing the information; it’s all reportable material. That said, I do feel bad for all the surprises being spoiled and, importantly, for the Apple employees who’ve worked so hard on all this stuff. But even with this deluge of information, we still have no idea how Apple’s going to telegraph the new iPhone and its features. There’s still much we don’t know, messaging-wise, so Tuesday’s event will undoubtedly be a good show in spite of these massive leaks.