For PowerPoint XP and 2003, go to View > Master > Slide Master. (View > Slide
Master for PowerPoint 2007)
You are given a default slide master at the start, which you can edit it.
And if you intend to apply different designs onto the presentation, you can
create mutiple masters. Have a look at: http://www.echosvoice.com/creatingmultiplemasters.htm
--
Shawn Toh (tohlz)
Microsoft MVP PowerPoint
(Amazing PowerPoint animations, artworks, games here) http://pptheaven.mvps.org
PowerPoint Heaven - The Power to Animate