Unfortunately, you can only get it from a Nintendo event which was held a long time ago in a distant land. Unlucky.
Unfortunatly, not -.-
No, it's only on E/FR/LG.
No, Deoxys is only in Emerald, and you need to migrate it to can catch it. As for Celebi and Mew, you need a cheat code for them.
It is impossible to catch a Deoxys in the wild in HeartGold & SoulSilver. You need to get one at a Nintendo Event or transfer one from a GBA game. Theres a Deoxys mission in the 3rd Ranger game. Capture it and it will be comfortable in any 4th gen game.
You cannot find Deoxys in Pokemon HeartGold. Deoxys has to be traded from another game to get into HeartGold. The rocks to the east of Pewter City are used to change Deoxys' forms, but you have to transfer one using Pal Park, first.
You cannot find Deoxys in HeartGold, or SoulSilver. You can only get Deoxys through trading or at a Pokemon Event.
you cant catch a deoxys in Pokemon soulsilver or heartgold but u cud trade it over from ruby Sapphire or emerald or use an action replay
No. Deoxys can only be caught in GBA games. To get Deoxys in HG, you need to transfer it from the Pal Park in Fuchsia City (I think) in Kanto or trade it from a game that does have one. However, I don't think the latter is very likely as Deoxys is a legendary pokemon and therefore quite rare.
You catch deoxys at birth island.
You can't catch Deoxys in Silver..
You can't
You can't catch Deoxys in soul silver