It depends what game your on about. If it be Pokemon Diamond or Pearl you could you a cheat or go to a Nintendo Event. If you don't want to do that:The Azure Flute is a device which is used to encounter Arceus. Since Arceus sits atop a special platform over Spear Pillar, you cannot use the walk-through-walls cheat to access it. That cheat, however, does work for Shaymin. But, you don't wish to use a cheat or attend a Nintendo event. Unfortunately, those are the only ways you can get the Azure Flute. Simply put, the Azure Flute is a Key Item (so it cannot be traded while it is attached o another Pokemon), it is not found by a Pokemon with the Pickup ability, it cannot be won or obtained in any other way than by hacking into the game or attending a Nintendo event (or, at least, linking up to one - perhaps by the WFC). You may get Arceus (the point behind the existence of the Azure Flute) by other means than the Nintendo Event or a cheating device. It may be available for trade through the Global Trading Station available via Nintendo Wi-Fi) or a friend of yours may have one. If so, you can trade Arceus to your game without the fuss of a cheating device or Nintendo event. It is highly likely that the trader will want a high-leveled or rare Pokemon in return, so be sure you have one worthwhile to trade. Really, though, the Azure Flute is a very exclusive item. You would be unable to find it without interaction of some sort with external devices - be it the Wonder Spot or an Action Replay. Or you could trade mystery gifts with a friend who has the item.