top iphone os 4.0 features?

New features include:

Include support for multitouch gestures, something that makes sense if you stick to the rumors that the tablet has the same operating system, and a function of this type would be necessary in a tablet, or at least appreciated.
It will improve the notifications, if this is true, thank you very much Apple engineers.
Synchronizing contacts and calendars renewed. Right now we can only do this via MobileMe, or using cable, something that makes the iPhone very good place in this regard.
Running programs in the background. Hopefully we can finally have our terminal multitasking because it is something that is on demand with insistence by users.
A graphical interface easier to use. Here, BoyGenuisReport people advertise a lot of improvements from what we see on the screen of the iPhone.
Compatibility with iPhone 3G and 3GS. At this point should be taken into account the consumption of the battery as much change can trigger. Let's see how they solve it.

Many new things for the iPhone OS 4.0 software, of which at least half expect to see them soon. It would be a good improvement over previous versions.

Apple today previewed the iPhone OS 4 and has provided a beta version of the software to members of the iPhone Developer Program (iPhone Developer Program). The beta version of iPhone OS 4 includes a Software Development Kit (SDK) with more than1,500 new interfaces for application programming interfaces (APIs) and more than 100 new features that will be available this summer for iPhone users and iPod touch.