Two Ways:
1. Use Action Replay
2. Wait for the Nintendo event, go to it, and have it put into your game.
You have to go to a certain Nintendo event to get one.
The "heavens pipe" or "Azure Flute" can be obtained by either a Pokemon event or an action replay
go to were the shamen is
where is heaven's pipe in Pokemon diamond i have the action replay
go to a Nintendo event to get heavens pipe then go to spear pillar stand on the symbol dialga was on use heavens pipe then stairs appear go up the steps arceus is there lv. 80
srry u have to go to a Nintendo event 4 it
you have to go to an event or use an action replay. the code is: Arceus 94000130 FCFF0000 B21C4EA8 00000000 B0000004 00000000 0000AA3C EDB88320 E000AA68 00000104 0000000A 00000000 D2000000 00000000 push l+r then talk to the guy in the green suit
The way to get to Heaven's Pipe (also known as the azure flute) in the game Pokemon Pearl is to talk to the man in green standing by the counter at every poke mart.
From serebii.net: The Heaven's Pipe can only be obtained through a Nintendo event so far. To use it, you must bring it to the location where Dialga or Palkia originally were. Upon bringing the Heaven's Pipe to this location you will have the option of playing it. When you do, a set of stairs will appear. These stairs will take you to the Beginning Dimension where the legendary pokémon Arseus resides. This is the only known use for the Heaven's Pipe so far
get heavens pipe go to spear pillar n stairs will appear walk to the Pokemon n battle him on level 80 Event-only, brah. Sadtimes to be sure.
Go to the Serebii.net,then look to the left,under the video game,then press on diamond & pearl.After that look to the right side and find The arceus factor and there will be some info about arceus. okay, hears the REAL answer. you ether need action replay or go to a nentendo event. so you need the heavens pipe or azura flute. go to the top of the peak (where you caght dialga/palkia) and the azura flute/heavens pipe should be making a strainge noise, blow on it and stairs should appear, at the top, arceus should be there! transform arceus by giving him the spoky plate, fire plate, water plate, ect. and transform him into any type of Pokemon!!! P.S you need to have the national pokedex and defeat the Pokemon league to use the azura flute/heavens pipe.
use the azure flute