Steve Jobs announced the headlines during Apple's 2010 special music event and they include Game Center social gaming network, TV rentals, iTunes Ping social music network, HDR photography, and HD video uploads. (Yes, Apple is introducing not one but two new social networks.)
More importantly for some, proximity sensor misfires, Bluetooth woes, and the abysmal performance on iPhone 3G appear to be fixed.
We'll be covering all of that and more below. For anything and everything that hasn't changed, check out our massive iOS 4 walkthrough because we won't be repeating all that here
Note: this walkthrough is based on the GM (gold master) version of iOS 4.1. We'll continue to add to and improve it as needed, and update once iOS 4.1 release version hits, probably on Wednesday September 8.