its here its great(er) and it has tons of new features. i cant name them all, mainly because im lazy and theres other posts to post, but heres a few of the cool ones:
• Multitasking: It’s here, finally. It’s handled with a simple task switcher: double click your home button, and you get a list of running apps. Select, switch, done. Multitasking is limited to audio streaming, VoIP and GPS apps, as well as a few other allowances: they can finish specific, important tasks in the background, for example. As far as non-music/nav/VoIP apps, those can be suspended in the background, but not left running. (See below.) Full details here.
• Fast app switching: With iPhone 4’s multitasking, most apps aren’t actually running in the background—just certain functions of the app, like an audio stream or a GPS lock. But! All apps can now be frozen, in full, so that when you reopen them, they’re restored to exactly the state they were in when they were closed.
• Local notifications: Notifications can be sent between apps on the phone, not just from remote servers. In other words, if something important happens in an app you’ve opened and moved away from, a notification will pop up in whatever app you’re using at the time, effectively saying “switch back to me!” It’s a fairly clever way to keep track of multiple apps without the need for a start bar or dock-type interface. From Apple’s dev guidelines: