In an all-round smart move, the TechNet folk have published the WAIK documentation online for your deployment pleasure. My favourite bits are where you can customise the Out of Box Experience (OOBE) and configure the Welcome Center and also what the user sees the first time they start Vista; things like configuring Wallpaper, Creating Users etc, etc.
This stuff is really useful for System Builders and IT Managers because they can offer services and additional software installations when the user loads up Vista for the first time.
Check out the documentation here:
Check out the Customisation Walk-thrus (Welcome Center and Vista first run experience):