There is no cheat you just need to catch shaymin using Oak's letter then the lady in floroma town will give you the key item Gracidea Flower and you can give to Shaymin and it will change form.
A Shaymin in Shaymin Village gives you a Gracidea. Use that while in a dungeon and he will change form.
get a Gracidea in the shaymin village in a dungeon use the Gracidea on shaymin + shaymin is in sky form effect removes if your at the next floor and sky shaymin sky forme is on double speed in Pokemon diamond,pearl&platinuam you get an gracidea,go to the Pokemon league then,there!
In Shaymin Village, If you talk to a certain Shaymin, it will ask you if you want a Gracidea. If you say yes, you will receive a Gracidea to use on the Shaymin on your team, wich will put Shaymin in its Sky Form. If you say no, wrong answer.
Sky's Summit (Summit)
Shaymin's sky form is a form that the Pokemon character Shaymin can take.
Yes, Arceus and Shaymin are both featured in Pokemon Explorers of Sky.
Arceus and Shaymin are in Pokemon Explorers of Sky,i dont know if its in Darkness.?
You can get Shaymin in sky form only in Pokemon Platinum Version.
skymin
You beat the game, go through Sky Peak once, but you have to complete it once more to get the Shaymin to join you!
Get the flower and use it on Shaymin to change forme.
shaymin