What I did was catch a Pikachu in Viridian Forest, then level it up until around 35 and gave it a ThunderStone.
You can't. You have to migrate from LeafGreen or FireRed.
It can be found everywhere on the map, you just have to have squirtle as your starter Pokemon
articuno, zapdos, moltres, suicune, entei, raioku, and mewtwo
master ball. but save it if you want it to use it on entei or raioku which run in the wild
You can't catch it on Firered you can only catch it in Emerald
You can't catch it.
you can not catch him
You can catch a Ho-Oh at Navel Rock in Pokemon FireRed.
You can catch Moltres at Mt. Ember Peak in FireRed.
You catch Ekans on Route 4 in FireRed.
You can catch one in the Safari Zone...
You can not catch it in leafgreen,but in firered you can.