module.provider() example

gistfile1.txt

angular.module('myApp', [])
  .provider('greeterProvider', function () {
    var greeting = 'Hello!'
    this.greeting = function (name) {
      return 'Hello ' + name + '!';
    });

    function Greeter() {
      this.greet = function () {
        return greeting;
      };
    }

    this.$get = function () {
      return new Greeter();
    };
  })
  .config(function (greeterProvider) {
    greeterProvider.greeting('World');
  });

In your controller, you can do this:

function MyCtrl(greeter) {
  $scope.greet = greeter.greet();
}