Or you could buy some vinyl decal material any color you want....
ORACAL 651 Intermediate Cal Vinyl 24" x 50 Yard Roll you could get enough to do your speakers for around $10 from any local lettering shop, super easy to do, my son did his bookshelfs by himself and they came perfect, exacto knife, spray bottle with water, soap, and alcohol, and a felt squegee.. Spray the sides of the cabinet start in a corner lay on the vinyl, squegee out the water and boubles, and move on, cut it down the last corner, lay a peice on top, cut out your speaker holes, and your done... then if you ever want to sell them just peal it off with a hair dryer...