Oh man, you're taking me back a few years XD. There was a program I remember for removing certain sprites from games, but it never really worked well. Most sprite rips you see are done by hand with screenshots. Some emulators allow you to remove certain layers of graphics, so that helps sometimes.
You might want to look here: http://gsarchives.net/index2.php
What game was it? [img]/images/graemlins/laugh.gif[/img]