The announcement is up here:

http://blogs.msdn.com/agile/archive/2010/04/20/microsoft-enterprise-library-5-0-released.aspx

Some of the things on the list of what’s new & improved

1. Redesign of the configuration tool – heck, that thing looked the same since the bits were acquired from Avanade quite a while back – good to see the changes.

2. Logging performance – this is has been 1 of the areas that we all need

3. Configuration improvements: XSD enabled, intelligence (yeah!)

4. Oh, and .NET 4.0 support :)