go to your settings in your dsi menu and set it to July 31 then go to wifi mystey gift it will give you the emiga stone then tack it to the guy who terns fossles into Pokemon he will tern it into a stone with dew in its name (steven the houen champ sead mado lateis/latios depends on your game and talks about the rair rock)anewaywhen its finished you tack it and go out side and hes there p.s i don't know if you have to chace him or her depends on your game i did it on my cusens game but had to go home befor i was dun but i think i got you this far so do the rest your self pss sorry i suck at spelling sorry hope i helped
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't get Latios in HeartGold. You can get Latias, to get her, talk to the copycat in Saffron and find her lost doll in Vermillion city at the fan club and Steven will be out there when you come out. He will talk about Latias for a minute and Latias will be in Kanto just walking around like Raikou.
You need to get latias ( can only catch it on Pokemon heartgold) and latios (can only get it on Pokemon soulsilver) and speak to steven who is in the silph co. in saffron city.You must get the Enigma Stone from the WiFi event, which turns out to be the Soul Dew.
It doesn't matter what Pokeball you use. If you have the Master Ball left over, you could use that to catch Latias. However, Ultra Balls will work the best if you do not have the Master Ball. I'm guessing you don't have a Master Ball since your asking this question, so the best ball to use would be an Ultra Ball. Sometimes it takes more then once to catch a Pokemon, so you just have to be patient and try not to freak out like me when Latias runs away after chasing it for hours. :D
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
you need your national poke decks to do this look on the map on your pokegear it wil show where latias is
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.