Angular2 i18n at this point?

Plunk was updated to Angular 2 Final: https://plnkr.co/edit/4euRQQ. Things seem to work the same as in RC7.

New i18n section has been added to Angular 2 official docs. Basically, it explains in details what happens in the plunkr above.

XLIFF is the only format for translations, no json support.
A translation source file (xliff, xlf) should be created using ng-xi18n tool:

package.json:

"scripts": {
  "i18n": "ng-xi18n", 
  ...
}

and

npm run i18n

See the Merge translation section for details about merging a translation into a component template. It’s done using SystemJS Text plug-in.

Another example using Gulp http://www.savethecode.com/angular2-i18n-native-support/

Older staff:
Update based on RC7 and links provided by Herman Fransen:

I’ve made a minimal Plunkr example: https://plnkr.co/edit/4W3LqZYAJWdHjb4Q5EbM

Comments to plunkr:

• bootstrap should provide TRANSLATIONS, TRANSLATIONS_FORMAT, LOCALE_ID with values -> setup translations
• translatable items in html-templates should use directive i18n
• translations are stored in .xlf file. Ties between languages is done through Id, ties with html by a value of <source> tag in xlf
• currently xlf files are not used directly; a .ts file is manually created to wrap the content of xlf in an exportable variable. I guess, this should be working automagically in final release (maybe even now).

This is the first officially documented approach I found.
However, it’s still barely usable. I see the following issues in the current implementation:

• Language is set at bootstrap, unable to change it in run-time. This should be changed in Final.
• Id of a translatable item in xlf is generated SHA. Current way to get this id is a bit messy: you create a new translatable item, use it, copy SHA id from error and paste into your i18n.lang.xlf file.

There is a big documentation pull request concerning i18n

Older staff:
Release notes https://github.com/angular/angular/blob/master/CHANGELOG.md have a record

i18n: merge translations 7a8ef1e

A big chunk of i18n was introduced in Angular 2 RC5

Unfortunately, still no documentation available.