iphone os4

Okay, I know this is very overdue, but Apple has released a preview for the iPhone OS 4.
First, I'm sure you heard about that guy who worked for Apple who was nesting the iPhone 4, and left it at a bar. A guy proceeded to pick it up and sell it to Gizmodo for chrissakes. The whole story is here, and the new iPhone is here. They can't turn it on though, because Apple conveniently remote-wiped it.
There are a few little looking new touches. Like the place where you keep those four apps that are always handy in any screen: that mesh aluminum kind of background has been replaced with a glassy like reflective table, like one on a Mac. Encrypted e-mail too, so you'll have the option to be required to enter a pin to go into the Mail app. Exchange Server 2010, and VPN support too.
Homescreen Background
All the those whiny teenagers won't have to jailbreak anymore in order to change the background of their homescreen. I don't think that it looks very finished, but at least Apple is listening to their customers.


Multitasking
Jobs claims that the reason that it took them so long to come out with multitasking, is that they were trying to develop a way to multitask without straining battery life, or reducing performance, and they have (apparently) finally achieved this. I'm going to have to see it to believe it. It works by double-tapping the home button: the screen will rise up, and you can select an open application from the menu. It's kinda like Quicksilver for the iPhone. You can even use your iPod controls in your lock-screen with Pandora running in the background. You can receive Skype calls, and do other things while talking. Imagine how cool this will be when coupled with the front-facing camera as seen on the prototype? You can even receive calls while in the lock screen. This is BIG. This is innovative. Why couldn't they have done something this cool with the iPad?

Folders
You can organize apps however you please. Just hold your finger on an app until it starts to jiggle, and the drop it into another app. Voila! A cool feature here is that it notices, say, if you are making a folder of games, that you have two game applications, and automatically names the folder. You can, of course, rename it as well. Tap the folder, the screen slides up, and you just select the app you want to launch. It's that simple. You can now have 2,000 apps on your phone now, thanks to Folders. (and Spotlight, thank you Jesus)

Unified Inbox
Business owners rejoice! There has been a huge demand for this. Now you will be able to have all your emails from all your email addresses in the same screen. Also, threads to follow conversations easier, adn multiple exchange support.

iBooks
It's just like the iPad. "e-Reader in your pocket". Not much to elaborate here. Free Winnie the Pooh, too!

iAd
Wins the award for worst name in the history of advertising, it even beat the iPad! So now developers will have a easier way to fill those "light" apps with advertisements. It works by making an ad pop up after a specified amount of time. Pop-ups: there's an app for that. Oh, and Apple gets 40% of the revenues. "It's all done in HTML5, by the way" Jobs said, which got a laugh out of the developers.

The majority of these features won't be available for the previous iPhones, and most of the iPod touches; the hardware just can't support it.
This is a general overview, but there is much more! Watch the Keynote- Watch / In HD