In the Microsoft Deployment Toolkit (Lite Touch and Zero Touch for SMS 2003), as well as in ConfigMgr 2007, drivers are added just-in-time to a Windows Vista image as it is being deployed (after it is placed on the disk, but before it boots for the first time). This is done using the PKGMGR.EXE utility or the underlying APIs to add new drivers into the Windows Vista driver store, a special directory structure (located in C:\WINDOWS\system32\DriverStore) that Windows Vista uses to hold both in-box drivers and "trusted" third-party drivers.
It's worth noting that after MDT injects the drivers into the driver store, it no longer needs the local copies in C:\Drivers; they will be cleaned up later in the process.
It's also possible to add drivers later, after Windows Vista is up and running (online), using PNPUTIL.EXE, a new utility for interacting with the driver store. (Want to get really fancy? You can even self-sign unsigned drivers. See http://technet2.microsoft.com/windowsserver2008/en/library/4bbbeaa0-f7d6-4816-8a3a-43242d71d5361033.mspx?mfr=true for the details.)
Let's say you just want to see what additional drivers have been added to the driver store. That's pretty easy to do using PNPUTIL.EXE. Just issue this command:
This will show a brief listing of all third-party drivers present in the driver store. You can also delete third-party drivers (one at a time) using PNPUTIL.EXE -d, add drivers into the driver store with PNPUTIL.EXE -a, etc.
There are some other driver management improvements in Windows Vista worth mentioning: