By Kevin Whinnery, published on June 27th, 2013, this tutorial explains how to integrate a Windows Azure Mobile Services application with a native iOS project and use the Twilio Client SDK for iOS to enable VoIP calling. The author guides readers through setting up their own Windows Azure account, creating an iOS project using Xcode, and integrating the mobile services backend into the app. They then demonstrate how to display clickable phone numbers in the app's table view cells using a third-party component called TTTAttributedLabel, and finally use Twilio Client to make outbound VoIP calls from the app. The tutorial concludes by highlighting the benefits of using Windows Azure Mobile Services and Twilio Client for mobile app development.