SQL Server 2008 Service Pack 1 CTP is an update to SQL Server 2008 which provides customer feedback driven fixes into a single service pack, minimizing deployment and testing complexity. In addition to all previously released updates, SP1 will contain changes focused on addressing reliability and performance issues in addition to adding support for several emerging standards.
The CTP version of SQL Server 2008 Service Pack 1 is now available at Microsoft Download Center. You can use the downloadable packages to upgrade any SQL Server 2008 edition including SQL Server 2008 Express. These packages have been made available for general testing purposes only and should not be deployed in production environment.