It's a Mew in there. Push the truck asid and find out.
near the surf house
go on the islands its on the fith one, near the cave
In Fuschia City, near the Pokemon center.
it is the power plant which is somewhere near the rock tunnel entrance.
You find one on five island, near the memorial pillar
Safari zone section 2 in the grass near the water
after u pass the Pokemon league u can find him randomly in the water near pallet town
You find a metal coat near the memorable pillar on five island.
He is in the one island Pokemon center he's the guy with the glasses near the big machine.
a lady in celadon give you a cup of hot tea. she is in one of the tall buildings near the Pokemon center
Its called the vs seeker and you get by going in the vermillion city Pokemon center and speaking to the girl near the nurse.
It is believed that Chansey is the rarest Pokemon of all to catch in Pokemon FireRed and LeafGreen. It can only be found in the Safari Zone, near the north half of it.