no
You cannot obtain Arceus without hacking or cheating.
As of now, there is no way of catching Arceus without cheating or hacking.
The arceus event is already over, so now you can not get him without cheating.
you hack instead! lol :P jks. You can get it in events but not possible without events of cheating OR hacking
You can only obtain it from cheating or hacking or trading with someone who has done so or you can wait for a Nintendo event to happen if you have a lot of patience
Hacking? You could also trade... but if you want the 'Fateful Encounter' Arceus, Shaymin, or Darkrai, I'm afraid you'll have to make do without.
Without any sort of event or hacking device, Arceus is impossible to obtain. Of course, trading is always an option.
by hacking
yes
NO only with a arceus flute.
The only way you can get Arceus in Heart Gold without cheating is to trade it from a game that already has Arceus.BTW, your question was in the wrong category, so I'll fix it.
Gamestop holds an event which has already passed but if you look up the code for the Pokemon modifier you can receive arceus.