http://www.raywenderlich.com/32960/apple-push-notification-services-in-ios-6-tutorial-part-1

Follow the steps in the toturial, but once you get to the end of Making the App ID and SSL Certificate and before you start Making a PEM File you should do the following:

Keychain Access > My Certificates Double click on the aps_development.cer "Export Apple Development iOS Push Services: "