Yes, just level Eevee up in Eterna Forest.
In Pokemon Diamond/Pearl, you find a old man at route 212 with a Leafeon.
Empoleon,Luxray,Honchcrow,Rapadish,Leafeon,and Garchomp.This is not including legendaries.
By trading across from either Pearl, Diamond or Platinum version
You have to get it from a friend who has Pearl/Diamond/Platinum
Am not sure if this works but go to Brook's map a search there for a leafeon.
(dim wit) You can't catch them in Pokemon Leaf Green because Leafeon and Glacieon was discovered in the Sinnoh region (Diamond, Pearl, and Platinum).
You'll need to trade for it from Pokemon Diamond, Pearl, or Platinum.
you get a leafeon by going to eterna forest with an eevee. Go to the mossy stone(hidden so use some repels)then level up your eevee and it will evolve into a leafeon.
you can't. there's no moss-stone to evolve it, so you'll need to trade it from diamond, pearl or platinum
Eevee can't evolve into leafeon in soulsilver you have to trade it to diamond and pearl and evolve it there. The ilex forest doesn't have a Mossy Rock - which is what evolves eevee into leafeon.
level up eevee near it and it evolves into leafeon.
To get both leafeon and glaceon in Pokemon soul silver or heart gold you have to trade it from diamond pearl or platinum.