Read the original post by Kunal Chowdhury at Kunal's Blog
In the last blog post, we learnt “How to Call a Number in WP7 using the PhoneCallTask?” We also learnt, “How to Save Phone Number in WP7 using the SavePhoneNumberTask?” So, how can you programmatically retrieve a phone number from existing contact list?
This post will help you to understand it. After reading this post, you will be able to programmatically retrieve the phone number in your application (this requires user’s interaction) using the PhoneNumberChooserTask. Don’t forget to read the complete post as this will help you to know about the internal implementation of the SDK API too.