The much anticipated enterprise library from Microsoft Pattern and Practice team has been finally released:

http://msdn.microsoft.com/architecture/default.aspx?pull=/library/en-us/dnpag2/html/entlib.asp

I am lucky enough to attend a seminar by Hisham Baz at Inland Empire .Net user's group meeting (http://www.iedotnetug.org/). Hisham is a developer of Enterprise Library. His blog points to many other blogs by Enterpise library architects and developers, together providing very useful information.