You'll need to trade for it from Pokemon Diamond, Pearl, or Platinum.
I think Leafeon and Iceon are only in diamond pearl and platinum. The only other way to get it is by trade. If you have multiple Ds's, you could transfer to heartgold. This works for Soul Silver too.
trade from diamond/pearl/
no have to trade from dppt
It cant
use a grass stone on eevee;-)
heartgold but you can get vulpix in soulsilver
To get both leafeon and glaceon in Pokemon soul silver or heart gold you have to trade it from diamond pearl or platinum.
HeartGold and SoulSilver are DS remakes of Gameboy versions Gold and Silver.
you cant get glaceon or lefeon in soulsilver
You have to get it from a friend who has Pearl/Diamond/Platinum
you can't get to any of the Sevi island in Pokemon Heartgold and soul silver
ilex forest