Official events are the only way to catch Arceus.
It is from an Nintendo Event.
you need the azure flute which you can obtain from a Nintendo event.
The only legit way to obtain Arceus is by attending a official Nintendo event.
you must get arceus via trade from Pokemon Diamond, Pearl, or Emerald. which you must get in the first place from a Nintendo event.
So far, there is no Nintendo event to get Arceus for your DS or DSi.
You would have to go to a Nintendo event to get a certain item.
You need to get it by a special Nintendo event or if you have a action replay and it is not called the arceus flute I am pretty sure it is called the ASSURE FLUTE.
in 2010
the is now way without using action replay or gameshark to get arceus because the Nintendo event for arceus hasn't even been released in japan!
there was none that i know of...
In Japan in December 2010
The azure flute is a event item from Nintendo. This item was used to summon Arceus a legendary Pokemon in the Sinnoh region.