migrate and trade
I put a link to a guide all about legendary pokemon in HeartGold in the related links.
there are many legendary Pokemon in Pokemon heartgold, but the best is HO-OH
In HeartGold you can catch Kyogre.
afther you beat all the johto gym leders.
Articuno
mew
There isn't currently a code for all of the legendary pokemon, but they each have individual codes in Heartgold DSi Action Reply. check out this guy's channel on YouTube. He has most of the legendary pokemon DSi Action Replay Code for Heartgold. ☺ :)
I don't think you can refight any legendary Pokemon except the wandering dogs.
Kyogre is only available for Pokemon: Sapphire on the GBA. Ho-Oh is the legendary pokemon available to you in HeartGold.
No legendary can lay an egg except for manaphy which gives an egg to phione and you can not get manaphy or phione in heartgold
yes at supercheats.com/pokemon heartgold action replay codes
Ho-ohLugiaCelebiJirachiLatiasLatiosSuicuneRaikouEnteiZapdosMoltresArticunoMewtwoKyogre-HeartgoldGroudon-SoulsilverRayquazaPalkiaDialgaGiratina