Notifio - Free and easy mail notifications for your iPhone
If you are moving from the blackberry to the iPhone, or just a new iPhone user, you may be disappointed to know that the only real mail notification for the iPhone is the ‘ding’ that you here whenever it comes in. Whereas on the blackberry you get a small flashing light on the top of your phone, and in some models you can customize the color based on the person that sent the email.