I would think it would depend on the effect you desire. I have had commercial lazer inscription done on a acrylic wedding pen, but if it's a cheap cartoon illustration, I would probably save money and just do a decal. And here comes BradG with another way. I guess I hadn't thought about what type of material you would be lettering. I would not recommend one of the little red vibrator buzzies, that makes your hand tingle and runs all over the place!!!!!
If wood or acrylic, lazer engraving. Find a local trophy shop and check with them. If it is acrylic, you will most likely need to fill it in with some color as it doesn't show up well, just has a frosted look.
As mentioned, find a trophy shop. I found one (when I lived in Indy) that engraved everything I took to them. After engraving, I filled it with Rub n Buff from art supply store. One thing though.....it will fill EVERY little scratch on the surface. Make sure you have a perfect finish before using it. DAMHIKT :redface:
There may also be a member here on IAP who can engrave it for you.