you get it in the Ilex forest
Headbutt is no a HM in Pokemon soulsilver. However a man in Ilex Forest will teach it to any Pokemon that can learn it.
headbutt trees
headbutt trees
There is a boy in the Ilex forest (West of Azelia town) who gives you headbutt.
use headbutt on trees
By using Headbutt on a Tree.
Many Pokemon can at the beginning if you choose totodile it can learn headbutt.
Headbutt dosn't come in a TM. You can teach a pokemon Headbutt by talking to a guy in a pink shirt in the Illex Forest. You can Headbutt trees (Like an HM) to find certain PoKeMoN.(It vairies where you Headbutt.)
Note: You need Headbutt.New Bark Town Headbutt Trees.CherryGrove City Headbutt Trees.search him on your pokedex and it will be red instead of green that means you need to headbutt a tree using headbutt.
it call headbutt and there is movetutor in ilex forest that teach it to you
headbutt a tree(close 2 ecruteak city)
Headbutt trees near mountains