Window Vista Sp1

Microsoft confirmed its RC rollout plans on December 5. This Wednesday, the company made the Vista SP1 RC bits available via Microsoft Connect to the same 15,000 testers it provided with the RC preview. On December 6, Thursday, Microsoft made the Vista SP1 RC bits available on the Microsoft Developer Network (MSDN) and TechNet, officials said. And on December 10th, Microsoft plans to make the Vista SP1 RC build available to anyone interested in downloading it from the Microsoft Download site

http://blogs.zdnet.com/microsoft/?p=1013&tag=nl.e622And you can download the Windows Vista Service Pack 1 Beta Overview

http://www.microsoft.com/downloads/details.aspx?familyid=090DEAF6-2EAA-4AAA-8B3B-2E199DB4A97D&displaylang=en