you need your national poke decks to do this look on the map on your pokegear it wil show where latias is
In pokemon Heartgold
you can't, but you can catch latios in ss and latias in hg hg(Heartgold) ss(Soulsilver)
it roams kanto after you get it on the marking map
Donphan, Growlithe, Gligar, Latias, Kyogre, etc
after that, someone at the battle frontier will tell you about latias and latios. then, latias will start roaming kanto.
In the pewter city museum. to get his attantion you must bring walking latias ( heartgold) or latios ( soulsilver ) with a soul dew from a mystery gift. then he will take you to saffron city. he will talk to you for a while. then he will go back to pewter then show you latios ( heartgold ) or latias ( soulsilver ) outside of the museum. then after you defeat or catch one of eon Pokemon that's the last of him.
You can only catch it when steven talks to you in vermilion city when you try to get the doll for the copycat. You catch it the way you caught raikou and entei
Nothing happens after you see him but, if you catch Latias, he'll see you again
That depends on what you have done before. Nothing special happens after you catch rayquaza. If you haven't done it yet, you can catch Latios/Latias.
master ball, paralyze and block, false swipe and random balls
Yes, Mewtwo, Latios and Latias will be in HeartGold and SoulSilver.
Yes in fact you can. To start roaming latias get the clefairy doll from the man in vermilion and step out the door and latias will roam. To get latios, you need to get the enigma stone from wifi.