Today we released the Beta versions of the Service Packs that will be shipping for .NET 3.5 and Visual Studio 2008.

• Visual Studio 2008 Service Pack (SP) 1 Beta
• Microsoft .NET Framework 3.5 Service Pack (SP) 1 Beta

Please note that the betas are intended as a mechanism to allow early testing and feedback. As a beta release, it is recommended that you only install the service pack on test machines.

What is new with these Service Packs?

There are several bug fixes and enhancements, the most notable ones I'm listing in here.

• WPF enhancements: more controls, a streamlined setup, improved start-up performance, and powerful new graphics features. See Channel9 post for more details.
• .NET Framework Client release ("Arrowhead"): this is subset of the full .NET Framework 3.5 SP1. It allows for faster setup on client machines not yet running version 3.5 of the .NET framework. This new setup installer enables a faster, simpler installation experience for .NET applications on Windows XP and Windows Vista.
• ASP.NET Dynamic Data
• ADO.NET Entity Framework
• ADO.NET Data Services (codename "Astoria")
• The .NET Framework Data Provider for SQL Server (SqlClient) adds new support for file stream and sparse column capabilities in SQL Server 2008.

Update: Review the complete, extensive, detailed list of enhancements on ScottGu's blog. As always, Scott's post gives you all possible information you need on this.

Compatibility issues with Silverlight 2 Beta 1 tools

Note that there are a few known incompatibilities with this service pack including: Expression Blend, the Silverlight 2 Beta 1 SDK, and the Microsoft Silverlight Tools Beta 1 for Visual Studio 2008. A new version of Expression Blend 2.5 March Preview has been released here that is compatible with this service pack.