Mew cannot be caught in HeartGold. Mew cannot be caught in SoulSilver, either. The only two ways you can get Mew are by trading for it or by getting one through a Nintendo event. It will be easier if you trade for one.
To get a Mew in Pokemon Heartgold, you could do it through a Nintendo Wi-Fi event.
Yes you can if you have Mew in your Pokemon SoulSilver/HeartGold You can put Mew in the Pokewalker.
yes
An event
yes
Mew
mew
Mew can't be catched in Pokemon heartgold, only mewtwo.
you cant for heartgold or soulsilver suckers
you can't
Nintendo event
You cannot get one.