One of my co-workers Chris Henley just did a great video/screencast on WinPE.
What Exactly Is WinPE?
Have you ever done custom setups of Windows? Have you ever needed a small version of the OS to boot a box and troubleshoot hardware issues? WinPE, Windows Preinstallation Environment (Windows PE), is a minimal Win32 installation that controls the early boot process and initiates the deployment of Windows Vista, Windows XP, and Windows Server 2003 onto the computer.
It's part of the Windows Automated Installation Kit (AIK) which is designed to help Original Equipment Manufacturers (OEMs), system builders, and corporate IT professionals deploy Windows onto new hardware. The Windows AIK is a new set of deployment tools supporting the latest release of Windows. This guide describes the current methods, tools, and requirements for deploying Windows.
You might also want to download the Windows Automated Installation Kit (WAIK) User's Guide for Windows Vista.
Chris shows you step by step how to do this! Great 17 minute video!!
Click here to Watch The Video.