You beat the gym leaders, elite 4, and the champion of a region of your choice, and the legendary Pokemon from that region can be randomly encountered.
You have to defeat the elite four then you can catch the legendary
you have to get more then 45 gym to catch legendary Pokemon! deoxys is a legendary Pokemon
you can catch as many legendary Pokemon but only once unless you have it on the computer
you can't catch it because you already beaten the legendary
defeat all gyms,elite 4 and champion of that region to catch legendary pokemon
Check the link. Go there for the legendary pokemon.
You catch them with a ultra ball
Yes I've done it before.
no
no
to catch zapdos in pokemon black you have to have every legendary pokemon
you first have to catch/defeat the legendary pokemon cobalion in mistralion cave you catch virizion in pinwheel forest