This is what you have to do to index the sprite
1. Make you pokemon 64x64
2. Choose a color that you did not use on the pokemon
3. Put that color in the background surrounding the pokemon
4. save the pokemon
5. Open the pokmeon in infanview
6. Decrease color depth to 16 colors 4bp
7. To index go to the color that you did not use in the background and double click it. Memorize the numbers and then type those numbers into the farthest color to the left. I think it would be originally black all of the time.
8. Save the new sprite.
9. Open the old sprite and copy the image.
10. Paste the old sprite on top of the new one.
11. Save it!
12. Open up unlz or your other pokemon editor and insert it in your game.
For more answers look here http://www.youtube.com/watch?v=-de01P3Rm5Q&feature=related