What is the best way to implement the internationalization for a Angular 2 Application at the moment?
The official i18n angular2 will be implemented in one of the rc release before the final release. It also will be more advanced than the current solutions.
More info how the new concept of i18n works in angular2:
UPDATE 6 SEPTEMBER 2016:
Support for i18n is now official in Angular 2 RC6
Official release blog:
A sample of internationalization with Angular 2 RC6