Big news today is that Apple has made iTunes 9.2 and the iOS 4 firmware upgrade generally available. This means that existing iPhone and iPod Touch owners will start to upgrade to the new OS. Just as important for developers is that Xcode 3.2.3 and the iOS 4 SDK are now out of beta and available for download. As far as I can tell this is the same software that was previously made available as the GM release. I also assume that this means it is no longer covered by an NDA and we can start to talk about it.
No news yet as to when we might see wider developer access to the pre-release of Xcode 4 (beyond attendees of WWDC).