Slipstreaming, it’s a known term that is known by pretty much people. With Windows OS client and server software and Office products it is a known proces. Why shouldn’t you integrate a service pack with the original installer, it will save you a lot of time.
With Exchange 2007 this is not possible anymore, you may think this is strange, this was my first reaction also. Then I searched further and discovered that slipstreaming is not necessary anymore. You just download the latest trail version from the Microsoft website and install it. When finished you will fill in the key and you are ready.