A lot of people try to match their PC game profiles to the way a controller is setup on the PS2 or Xbox, so if you want to find out the layouts of the controllers on those console systems... there are TONS of manuals located at the following links, so you can check em out...

http://www.replacementdocs.com/download.php
http://www.videogamebuttons.com/
http://www.gamesegment.com/
http://www.allgame.com/
http://www.gamefly.com/