I heard that there is another way to catch Celebi in HeartGoldSoulSilver other than the events on the official website or the promo events.

 

Can someone tell me if I can catch him or not????

 

I heard before that if you catch all Unown letters and go to the shrine then Celebi will appear but I don't know if this is true or not

Sorry, but Celebi is only distributed through the special one-time events that have long since ended. The only way to get one now is to use an action replay. However, you might be able to find some people willing to trade one on the GTS. Unfortunately  you have to have SEEN Celebi in order to be able to trade for one. It's complex stuff, so you might want to look it up on  serebii.net. They have a section dedicated to Celebi called, "The Celebi Factor".

Mmm..I don't think you can catch Celebi outside of promo events in those games. Now, I may be wrong, but it's best to check websites like serebii.net for information regarding how/where to catch specific Pokemon.

Celebi isn't obtainable in-game, only through old distribution events. 

Cheat codes or events

That's sad,considering that the only way to battle Giovanni in HeartGoldSoulSilver is by finding Celebi.Man if I was aware of those events earlier

Is it even possible to trade it? IIRC there were some events which you could not trade, eh?

There is an AR code for it if you want, but to obtain it legitimately, there was an event. 

 

 

I regret ;-;