Slap on a N-CQ label on it and you're done. it won't glow unless the U.V. light is on but it still looks really cool.
here's what it should look like:
http://0.tqn.com/d/chemistry/1/0/D/f/glowingtonicwater.jpg
I didn't make this it's just a picture I found.
I should also add that if you want to do this you need to use a florecent black light, not an incandecent. The filiment in the bulb will produce too much visable light, and you won't be able to see the glow.