Nintendo event
To get a Mew in Pokemon Heartgold, you could do it through a Nintendo Wi-Fi event.
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.
An event
Store 999 Pokemon in Pokemon in my Pokemon ranch for he Nintendo wii and Hayley will give you a mew and it was a event
No. It is an event pokemon, or you can hack it which I don't recommend.
On heartgold, it is only available through a Nintendo event. But another way is to trade from another game, where you might have caught mew. Hope I helped!
you get it from event that Nintendo going to release. it all ready released in japan
Without hacking, there isn't a way to catch a mew without a Nintendo Event.
Nintendo event or action replay
You needed to get it from the 10th anniversary Mew event that went on in October 2010. If you didn't get it from that event then you need to cheat
Its not possible to get mew in firered only emerald can via Nintendo event.