Near the apricorn tree. :)
Move around the map until you see Route 38.
Houdoom is best know for being a Pokemon featured in Pokemon Soul Silver. A person can catch Houdoom by visiting Route 7 during the night time, at level fifteen.
evil Pokemon
if you have surf then anywhere with water
Swablu is only available by swarming on Route 45.
in Pokemon soul silver catch it in route 36, route 37, and route 48. (Note that i don't know if it is the same for silver)
In Route 38.
No.
in Pokemon soul silver you can find it at route 36 or route 35
On route 34.
You get sneasel in Route 28 silver cave (Night)
Ditto is found at Route 34,Route 35 and Route 45
You cannot get it in Pokemon Silver, but you can in SoulSilver or HeartGold. You have to go to Route 36.
Dratini in Pokemon Silver can be found in the Dragon's Den or on Route 45.
Headbutt trees on route 38
route 14
at route 28 at night