Just released about an hour ago.

http://msdn.microsoft.com/en-us/vstu.../cc533447.aspx

.NET-based Windows application development benefits from increased Windows Presentation Foundation (WPF) designer performance and updated components for Visual Basic and Visual C++ (including a MFC-based Office 2007 Ribbon). Web development improvements include enhanced the client-side script tooling (JavaScript IntelliSense). In addition to IDE performance improvements SP1 fully supports SQL Server 2008 and the ADO.NET Entity Framework.

The .NET Framework 3.5 Service Pack 1 (SP1) delivers more controls, a streamlined setup, improved start-up performance, and powerful new graphics features for client development and rich data scaffolding, improved AJAX support, and other improvements for Web development. Additionally it introduces support for the ADO.NET Entity Framework and ADO.NET Data Services, which simplify data access code in applications by providing an extensible, conceptual model for data from any data source and enabling this model to closely reflect business requirements.