There IS a gameshark code to get a g/s ball...
seee, they didnt leave Celebi out of thge Game, but they DID leave out the G/S Ball. Using this cheat gets it for you
Talk to kurt....
Read this from the Pokemon Crystal Forum
"Appearently, Celebi IS still in the game. All of the sequence that lead to it are also in the game. The only thing that isn't in the game is the GS Ball. Now, if you recall an eariler code I gave, it was to get you the GS Ball. With the new code I found, you only need a Pokémon Crystal, and a Gameshark. Enter the code 01C089DA into your gameshark, and talk to Kurt, the PokéBall craftsman. He will talk about your GS Ball, and give it back to you. Go back into the Ilex Forest, and talk to the Shrine. It will say the normal stuff, as well as something about a hole in the shrine. If you put the GS Ball in the hole, you'll step back, a Celebi will fly down and land next to you, and you'll come into a battle with a Level 30 Celebi! I don't know why they didn't use Level 70 or 60 or even 50, but level 30 was just too little. Anyways, the GS Ball could orriginally be obtained from the PCC in Goldenrod City, which was taken out of the game. So the only way to get Celebi so far is to use this Gameshark code, or 01FB04D2 , or you can go to a Six Flags Theme Park."
Any time...