How to call my own application instead of Phone Application when user press dial?

I am new to iPhone SDK and I would like to know if a simple thing is possible.
In its default operation, when a user clicks a phone number in Address Book, the iPhone opens the Phone Application and then dials the phone number.
I would like to know if it is possible either to:
1. instead of opening the Phone Application it would open my own application. I would "parse" the phone number and then open the Phone Application to dial the phone number.

or

2. "parse" the phone number string using a custom "parser" before opening the Phone Application to dial the phone number.

Thanks in advance.