What's New in SQL Server Installation
SQL Server 2008 has new Setup architecture for the following scenarios: installation, upgrade, maintenance, failover clustering, and command prompt installation.
The following features are new starting in SQL Server 2008 Service Pack 1:
Slipstream: Slipstream is the integration of the original installation media files with a SQL Server 2008 update, so that they can be installed as a single step. For more information, see the Slipstream section in Overview of SQL Server Servicing Installation.
The SlipStream parameters /PCUSource and /CUSource may change in a future release of SQL Server.
You can uninstall cumulative updates and the service pack from the Program and Features application in Control Panel. For more information, see the Uninstall section in Overview of SQL Server Servicing Installation.