you need a couple of dark Pokemon levels 60-70 that know dark type moves, that should be enough
You need Ho-oh and Lugia
yes but it is in pewter city
you need a silver wing
Yes. In whirl island but you need a special item.
you need lugia & Ho-oh :-P
You need to obtain the Silver Feather from a person in Pewter City. Once you have it, you can go to the bottom of the Whirl Islands and Lugia will be there at Level 70.
A person in Pewter City will give you the Silver Feather, then go to Whirl Islands. When you get to the end of the cave you will see Lugia.
In heartgold, Lugia is obtainable at the Whirl Islands but u need to obtain the silver feather from a guy in Pewter City. Once u have that silver feather, u can go deep into the Whirl Islands and find Lugia.
You will need to trade from HeartGold or SoulSilver or migrate Ho-Oh or Lugia from a Gameboy Advance game in order to be able to have Ho-Oh or Lugia in Pokemon Pearl.
If you are referring to HeartGold and SoulSilver, then you need to acquire the Silver Wing, and the Tidal Bell, and visit the Whirlpool Islands. For SoulSilver, you need the Silver Wing and Tidal Bell, and the Kimono girls will dance, summoning the Legendary. This is your chance to catch it. For HeartGold, you should see Lugia ahead of you, ready to catch.
deafeat gyms, catch,defeat,or run from ho-oh and defeat the whirl islands
once you have the silver wing off the old man in pewter city, you need to go to whirl islands and he is under them.