: We've all had the frustration of trying to deal with a pile-up of notifications on our device, only to realize that we've forgotten what one of them was after we dismissed it, or had it wiped off the screen by a subsequent alert. Now, all those notifications will be collected in a single location: Notification Center. Just swipe down from your device's menu bar, and you'll get a list of notifications, sorted by the application issuing them. On the iPhone, you can even get a quick look at your current weather and how your stocks are doing.

: Instead of getting those pesky dialog boxes, you can now configure alerts to appear as banners. They "flip" into existence at the top of your screen, with an icon that identifies the app, and a short message. Tap on one and you'll be taken to that app--leave it alone, and it'll flip around and disappear again, leaving you to continue your game, Web browsing, or email composing in peace.

: Instead of collecting your lock-screen notifications into one unhelpful blue blob, iOS 5 will provide you a handy list of messages you've gotten, without even requiring you to unlock your phone. Slide the icon next to any notification and you'll be launched right into that app.

Apple's shot at creating a BlackBerry Messenger-style service is iMessage, which lets you send free text, picture, and video messages to anybody else on an iOS device. Built directly into the Messages app, iMessage works over Wi-Fi 3G and lets you communicate via text message, for the first time, with users of iPads or iPod touches.