Enterprise Library 5 has been released by Microsoft Patterns & Practices. Enterprise Library 5 supports Visual Studio 2010 and .NET Framework 4. You can download the binaries here and download the documentation for EntLib 5 here.
You can find some Enterprise Library 5 Tutorials and Unity 2 Tutorials that I have written while EntLib 5 was in beta that are still applicable.
You can find all the details on Enterprise Library 5 on this landing page.
Enjoy!