Date: November 7th to November 15th
Where: Toys R Us!
Compatible: Diamond, Pearl & Platinum.
So like... =D I was browsing in Serebii and saw the awesome news of the Arceus Event coming son ^-^ Get your DS's and make your way to your local Toys R Us stores that are doing the event o_O Maybe if we are lucky we get some prizes along with the Pokemon like in the past events.
Anyway, attention to Platinum players ONLY,
The Arceus will unlock a speical event which gives a background story of Arceus.
For Platinum, Diamond & Pearl,
When you transfer Arceus to HeartGold or SoulSilver it unlocks a special area called the Shinto Ruins. From there the former Sinnoh Champion(Cynthia) comes and explains how Arceus can create a newborn pokemon. You can choose one from the three available.
Dialga(Lv. 1): Special Attack- Metal Burst
Palkia(Lv. 1): Special Attack- Hydro Pump
Giratina(Lv.1): Special Attack Shadow Sneak
Credits of Knowledge to Serebii