While Windows PE comes with a basic set of device drivers, you may need to add additional drivers to your Windows PE build environment to support certain types of hardware. You can add device drivers to your offline Windows PE build environment by using the Peimg command as follows:
Peimg /inf=path c:\winpe_x86\base
Here path is the path to where your device driver (.inf files) are located.
Alternatively, you can add drivers when running Windows PE by using the Drvload command as described in my other tip titled "Adding device drivers online to Windows PE".
For more information on deploying Vista, see my series of articles titled Deploying Vista on WindowsNetworking.com, and see also Part 2: Deployment in the Windows Vista Resource Kit, Second Edition from Microsoft Press.