The Windows Vista Team just blogged on a aspect of the Presentation mode in Vista - which allows you to prevent interruptions by system or messenger notifications during presentations.
You also have the ability to set a different wallpaper when in this Presentation mode (perhaps a corporate image?), I tend to favor a plain one as it is less distracting when I swap between PowerPoint and other applications on my desktop, such as when starting any demos using Virtual Server.
You can get access to these settings when a Network Projector or when an Additional Monitor/Projector is plugged into your mobile PC, you will see the New Display Detected dialog, from where you can Turn on presentation settings. Alternative run the Windows Mobility Center (from within Control Panel), and select Presentation Settings - I actually create a Quick Launch icon for this.