Whatever gameboy advance pokemon game you have.You will have beat the elite four then you trade pokemon on the game.

go to phenic city's pokemon center. go downstairs. there is a trade center

first you have to go to the pokemon center in phenac and go down the stairs and talk to the woman to trade pokemon

Have your connecter cord in but don't have it on until it tells you to (down stairs in the PC in Phenac) then save it then on your gameboy before you turn it off it will say Pokemon XD on your Gameboy.

It's true! I tried it and it worked!
Does any one else have all their legendary pokemon in Lv.100?
I do!
Don't challenge me because you won't stand a chance!

HEY!
Is it true that you can have Shadow Lugia in a game boy version?
A friend of mine said he had it!
At first I thought it was a lie, but then he kept bragging on about it and it got really
anoying!
Post me if you know anything!
I mean it...

Maybe its true, but that would require a MAYOR glitch.
Shadow pokemon cannot be traded.
Sorry I couldn't find out more...

Who was that jerk that said I wouldn't stand a chance?
I'm always looking for a challenge!
I'll take you on AND all your Lv.100 legends!

My closest encounter with a Lv.100 pokemon was fighting a Lv.100 Charizard a friend of
mine had.
I lost...
But, having all legendary pokemon in Lv.100?
That's awsome! I wouldn't want to fight that guy!