How to display notifications for incoming call using iPhone

I am planning to create an app to display an incoming call through notification. The way the app works is, if i am talking to someone through my iPhone to someone else and at the same time someone calls me, I cant receive the other call. So I am planning to create an app for it. Does apple provide the classes for it. I am newbie to XCODE. If i am talking on my phone and I am receiving a call, my app should only give a notification sound.