MSDN just published some pages describing each Application Blocks distributed in the Enterprise Library. And there is a good news written in the Roadmap:
“An updated release of the Security Application Block is planned for the next release of Enterprise Library. This release will target the .NET Framework 2.0 and Visual Studio 2005.
The Security Application Block will be updated to work with the .NET Framework 2.0 and may include additional improvements based on customer feedback.”