I dont know if this will help, but its taken from Court Records (Phoenix Wright fansite). Of course, adjust to whatever emu you're using, this guide was meant for PW sprites.
How to makes sprites:
1. Download AnimGet (once activated, it'll take snapshots of whatever window you open next every 10 milliseconds. Very handy for sprite ripping).
2. Open your rom to to the animation you want to capture and turn off layers 2 and 4 (this will get rid of the text box and background for the GS games, differs from game to game).
3. Open AnimGet and activate it. Return to the rom and let the animation play through. Once you have enough, tell AnimGet to save.
4. Find the folder labeled "shots" wherever you stuck AnimGet and there's your pics! I edited mine to make the animations in Adobe ImageReady, but I'm sure there are a lot of other programs you can do it in, too. Most of the sprites in GS don't use true black so cutting them off the background isn't hard.
If for some strange reason you despise AnimGet you can also use the Visual Boy Advance's .avi capture feature, or it's screen shot feature, or use enigmaopoeia's screen shots.