MAC:
How to Change Your Background on a Mac (Videos): http://video.google.com/videosearch?q=Ho
Mac 101: Change Your Screen Saver: http://support.apple.com/kb/HT2485
Mac 101: Change Your Desktop: http://support.apple.com/kb/HT2478
How to Change Your Screen Saver On Your Mac Computer: http://www.ehow.com/how_4551011_change-s
RonHow do I change the wallpaper?
Well, if you use firefox, you can right click on a picture, and select the option %26quot;Save as desktop wallpaper%26quot; and it'll do that, but I'm not sure if it'll work for MacBook Pro. Hope I helped.