There's something bugging me.

[Hendric]

In the new game that's coming out, Platinum, there's a key item that can change Shaymin between it's two forms. Does that mean that Shaymin might be obtainable in Platinum?

 

[Amewsment]

Like Mew, Celebi, Jirachi, Deoxys, Manaphy and Darkrai before it, it is an event-exclusive Pokémon That means either you attend an event that directly gives you a shaymin or in the future you will probably be able to acquire Oak's Letter through some event and capture it in-game.
The only alternative to events would be via a glitch for the Japanese version of D/P called the infamous "surf glitch" or for everybody outside of Japan the "tweaking" method to get to Shaymin.

 

[DashingFox]

Well I never thought about it but it would be nice if it was obtainable.

 

[SnorlaxMonster]

Like Mew, Celebi, Jirachi, Deoxys, Manaphy and Darkrai before it, it is an event-exclusive Pokémon That means either you attend an event that directly gives you a shaymin or in the future you will probably be able to acquire Oak's Letter through some event and capture it in-game.
The only alternative to events would be via a glitch for the Japanese version of D/P called the infamous "surf glitch" or for everybody outside of Japan the "tweaking" method to get to Shaymin.

But Mew is now available on Ranch and Manaphy hatches from the egg from Ranger.

 

[Amewsment]

But Mew is now available on Ranch and Manaphy hatches from the egg from Ranger.

My post was referring simply to the main series.

 

[Tadashi]

Unless you get the Glacidea Flower, you can't change Shaymin's form.

Right now, it's unknown if the Flower will be available in Platinum. It's also unknown if Shaymin itself will be obtainable outside of Japan. Like the Oak's Letter Event Shaymin that came in DP, it's possible that the Flower will be given away at an event.