In this blog post, David Anson explains how to localize a WP7 app that uses the Windows Phone Toolkit into different languages.
Source: Delay's Blog
While it might be convenient if everybody spoke the same language (or communicated via telepathy), that's not the world we live in. :) Therefore, building applications that can be easily translated to other languages is an important consideration. Fortunately, it's easy - and it's covered in the MSDN article How to: Build a Localized Application for Windows Phone. But what's not covered is how to localize the controls in the Silverlight for Windows Phone Toolkit. As you might expect, it's fairly similar, but I've had a few people ask about this explicitly and I decided to do a quick post on the topic. As long as I was at it, I figured I'd show the entire process from start to finish just to make things a little easier...