As you aware by now Silverlight 3 is now available on http://microsoft.com/silverlight

Below is a list of international features that have seen updated in this release.

1. Comprehensive documentation on localization : http://msdn.microsoft.com/en-us/library/cc838238(VS.95).aspx

2. Local Font support including Cambria and Segoe UI http://msdn.microsoft.com/en-us/library/dd547542(VS.95).aspx 

3. ClearType support (Tip: Greatly improved but use native resolution)

4. Merged Dictionary Support

5. Element to Element Binding

6. Bug fixs - Improved support for asian cultures on XP, thai input issue

Im still waiting patiently for the localized runtimes and tools but that is generally very quick after the main launch.

Anyway below is a sample enables updating UI strings in realtime without re-starting your application.

This uses a singleton class to the PublicResxFileCodeGenerator that implements iNotifyProperyChanged

public class LocStrings :INotifyPropertyChanged

    {

        // INotifyPropertyChanged plumbing

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyChange(String name)

        {

            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(name));

        }

        //public constructor

        public LocStrings()

           {

           }

        // PublicResXFileCodeGenerator

        private static loc.Strings lStrings = new loc.Strings();

        public loc.Strings LStrings {

             get {  return lStrings; }

             set {  NotifyChange("LStrings");}

         }       

    }

private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)

        {

            ComboBox langddl = sender as ComboBox;

            string selectedLang = (langddl.SelectedItem as ComboBoxItem).Content.ToString(); ;

            Thread.CurrentThread.CurrentCulture = new CultureInfo(selectedLang);

            Thread.CurrentThread.CurrentUICulture = new CultureInfo(selectedLang);

            ((LocStrings)this.Resources["LStrings"]).LStrings = new SL3Loc.loc.Strings();

        }

Demo: http://silverlight.services.live.com/invoke/6655/SL3loc/iframe.html

Code: http://cid-2b248d261d0e0035.skydrive.live.com/self.aspx/Public/SL3Loc.zip

BTW: SilverlightRTL updated their excellent code to work on SL3 http://blogs.microsoft.co.il/blogs/alex_golesh/archive/2009/07/10/silverlight-3-hebrew-and-arabic-support.aspx