How to Access Notification Center (iOS 5 & 6)

Just like the current Android system, the iOS 5 or 6 allows you to quickly access a notification by swiping down from the status bar at the top of the screen, saving you the trouble of finding alerts on the app icons in various home screens.

To clear a pending alert right away, press the X sign where available, and then the "Clear" button.
To access a notification, tap it and you're taken to the related email, reminder, message or app. The notification then clears automatically from the Center.

Better still, you can customize notifications the way you want from Settings > Notifications.