You can't find Elekid in LeafGreen, you need to trade an Electabuzz from FireRed and breed it.
Level 30.
The Pokemon that evolves into Electabuzz is Elikid
it is an item that is on an elikid when you catch it. the way to catch an elikid if you dont know is you have to have fire red in the gba port and go to route 205 when you have the nat. dex
no
go to stark mountain with a firered
Elekid > lvl 30 > Electabuzz
Find elekid on route 205 and Valley Windworks with Pokemon firered in your ds at the same time. Find magby at route 227 and stark mountain with Pokemon leafgreen in yourds at the same time. For both Pokemon you need the national pokedex.
breed an electabuzz if you want an elekid in Pokemon platinum
There's a Pokemon traner on route 210 that has a happily and a elikid
Catch Electabuzz (can only catch in FireRed- not LeafGreen), and go to four island (have to have beaten elite four and gotten 60 Pokemon in pokedex to go to four island). Leave Electabuzz and some other Pokemon (preferably Ditto) in the daycare, come back after a while, get the egg from the man, and it will hatch into an Elekid.
Elekid can only be obtained through trading in Pokemon Black. (Or transfering from a game with an Elekid)
To find an Elekid you must breed 2 electabuzzes which you can catch on route 222.