Please refer to my previous post for an explanation of what this integration does. The zip archive you can download contains two projects:
The Validation.Integration.WPF project contains the two classes EnterpriseValidationRule and ErrorProvider that you can use in your own projects (under BSD license).
The WPFValidation project can be compiled together with the validation quickstart from the Enterprise Library 3.0. It is the same quickstart sample rewritten for the WPF integration.
I would like to thank Tom Hollander from Microsoft Patterns and Practices for his encouragement to publish this code.
Let me know if you have any questions or feedback.