Sure, the iPhone 3.1 update delivered a host of new features, including the exceptionally tardy MMS, but for some users there was something extra: Crappy battery life.
To an email-syncing office drone with an iPhone 3G, this change looks like a bug. To an IT admin, this change actually looks like a bugfix. But no matter how you see it, Apple screwed up somewhere down the line.
iPhone 3.1 beta 2 now lets developers connect their phones to your development machine over Wi-Fi to run Instruments on; useful if you need to use your dock connector on the phone to connect to something else.