From Facebook Developer Wiki

[edit] Using Translations for Facebook Connect

Facebook is currently available in over 65 languages, thanks to a framework that allows our user community to translate the text on Facebook. By integrating with Facebook, you can take advantage of our Translations framework immediately, so you can enjoy the benefits that translation can bring to your Platform application or Facebook Connect website.

[edit] Getting Started

As part of the Translations for Facebook Connect, you can translate and make Facebook Connect sites, IFrame-based applications, and FBML-based applications available to Facebook users in every one of the 65+ languages Facebook supports.

The following steps assume you already have an API key and created an application or Facebook Connect integration. If you haven't already done so, create an application or integrate Facebook Connect now!

1. Prepare your application for translation.
   Facebook Translations is an opt-in framework to allow you to choose which languages you want to support. This article describes a few simple steps to indicate you want to support more languages.
2. Register the text you want translated.
   In order to get your application translated, you have to register the text you want translated using Facebook. This article describes how to register different types of content, offers best practices so that the translations are the best they can be, and includes some sample code to show you exactly how it can be done.
3. Translate your application.
   This article describes how you (or any Facebook user) can use Facebook to translate your application.
4. Administer the translation process.
   You always have complete control over translations for your application. Read this article to understand how best to oversee the translations as they progress.
5. Access your translations.
   We offer several ways to access the text you've registered for translation, as well as the associated translations.

[edit] Best Practices

If you're already translating your site or application, you should keep in mind these best practices.