David Anson has published this free PseudoLocalizer class which makes it easy to identify localization issues in WPF, Silverlight, and Windows Phone 7 applications.
Source: Delay's Blog
Two posts ago, I explained the benefits of pseudo-localization and showed an easy way to implement it for WPF - then said I'd outline how to do the same for Silverlight and Windows Phone 7. In my previous post, I went off on the seeming diversion of implementing a PNG encoder for Silverlight. With this post, I'll fulfill my original promise and unify the previous two posts! As you'll see, the basic principles of my approach to WPF localization translate fairly directly to Silverlight - though some limitations in the latter platform make achieving the same result more difficult.