you ned to go to www.codejunkies.com
No, you do not need all of the plates to catch Arceus. You can use the plates to change Arceus' type, though. Arceus is only available by event (which has long since passed). You can also use an AR (action replay) to hack the game and get an Arceus, all without plates.
there is none
i do not think there is a code try codejunkies.com if it is not there i do not know where to find it...
If you have Arceus, then all you have to do is give it one of the plates that can be collected around Sinnoh, for example, the Splash Plate. Then the Arceus will change its type.
You get them through out the game
No, but it helps if you do catch it. Arceus has a special ability called Multitype. When it holds a plate, it transforms into that plates preferable type. (E.g. Stone Plate = Rock Type, Zap Plate = Electric type). it is not proven when you get all of the plates arceus will appear, but what you really need the azure flute.
To put it simple, no. Any mart. Holding L & R then talk to the man in the green, he'll give it to you! :) Also, once you have Arceus, he can change colors. :) (Put different plates on him) Go here: http://www.serebii.net/diamondpearl/arceus.shtml to see all colors with plates. (Shiny and non-shiny)
You catch an Arceus with an event/ cheat code and make him hold it. The different plated changes his type.
This is the Action Replay for all 16 Arceus plates: 94000130 fdff0000 B21c4d28 00000000 B0000004 00000000 E000456c 00000028 31333a39 3b36302c 2d34352f 2e323738 00000000 00000000 00000000 00000000 00000000 00000000 D2000000 00000000 67546456 2aeeee28 12765575 88754448
all you need to do is get the azure flute. you must get the arceus event code.
See the following link for a complete listing of Plates and their locations: http://bulbapedia.bulbagarden.net/wiki/Plates
Find all plates and got to spear pillar................. TRICKED YOU....you need the Azure flute or action replay.