Slipstream is a common term used at Microsoft to define the merging of patches or updates into the original installation sources of a program.
What are the benefits of slipstreaming....
Creating a slipstream image reduces the operational overhead required to introduce a specific build of software to include Windows SharePoint Services 3.0 and/or Microsoft Office SharePoint Server 2007 into an environment. For example, if an organization has standardized on a specific set of updates and/or patches that will be applied in a given configuration, these updates and/or patches can be included in the original installation sources and subsequently installed with the source application. Slipstreaming a Windows SharePoint Services 3.0 and/or Microsoft Office SharePoint Server 2007 is a simple process providing you have access to the original and update sources...
Example (Windows SharePoint Services 3.0 + KB941422):
To install a specific Windows SharePoint Services 3.0 build such as 12.0.6039 which is the build number associated with KB941422:
When setup.exe is executed from C:\WSS, Windows SharePoint Services 3.0 (RTM - build 12.0.4518) will be installed and KB941422 applied during the installation process. The end result is an installation of Windows SharePoint Services 3.0 build 12.0.6039 without the requirement of installing KB941422 separately and the requirement of running the SharePoint Products and Technologies Configuration Wizard to upgrade binaries on each server machine in the server farm.
FYI I have just completed the install of Project Server 2007 + Service Pack 1 (and Office Server 2007
Until the combined source is available for a slipstream installation of SP1 with WSS/MOSS, you can utilize