Thanks to Radish for the heads up on this story from Windows & .NET Magazine
Now that references to Windows XP Service Pack 2 (SP2) and Windows 2000 SP4 are appearing in Microsoft documents, it's time to review the procedure you follow to combine hotfixes with a slipstream installation directory. Hotfixes that you might want to include in the current build can include updates you get from Microsoft Product Support Services (PSS), security hotfixes, updates you download through the Windows Update catalog (e.g., for an internal Software Update Services—SUS—Server), and fixes for OS components that are available for public download. Later in this article, I describe how you add hotfixes that update drivers to a slipstream version of the OS.
For those of you unfamiliar with the slipstream technique, a slipstream installation contains the original release of the OS (i.e., Windows 2003 Server, XP, Win2K) updated with the current service pack, plus any hotfixes you deem necessary for your site. A slipstream installation saves time when you're deploying many new workstations, and you want the system image to be fixed in time and consistent across the enterprise. If your images are well defined, you might want to distribute a new image every quarter instead of distributing 20 to 30 hotfixes per month to affected systems.
News source: Windows & .NET Magazine