There is an exception; Celebi can be caught in the Japanese version of Crystal.
This is how you do it, this is also 100% legit:
1. You have to obtain the GS-Ball by using the Mobile-phone hook-up link, which is NOT available in the US or European versions of the game.
2. Take it to Kurt in Azalea Town, he'll ask to you to give it as a gift to the shrine in Ilex Forest.
3. Place the GS Ball in the shrine and a Celebi will come down and attack you, giving you a chance to capture it.
Of course, this wouldn't help you with getting it onto Fire-Red.
Last edited by Yggdrasill; 07-22-2007 at 02:18 PM.