We are proud to announce that the ArcGIS Silverlight Toolkit is now available on CodePlex as an open source project.  The project contains the source for the ESRI.ArcGIS.Client.Toolkit.dll and is available for use under the Microsoft Public License (Ms-PL) agreement.  This source will be very helpful if you are customizing or extending the existing controls or if you are building your own mapping tools from scratch.

Inside the project is the Silverlight/WPF C# code and XAML for a set of widgets (controls) designed to work with the ArcGIS Silverlight Map control. You can find a complete list of components with help documentation on the ArcGIS API for Microsoft Silverlight™/WPF™ Resource Center under Library Reference.  

To learn more about CodePlex, please visit their FAQ page.

We hope you find this project valuable and we encourage you to participate in the developer community.

Enjoy!