evolve gastly.
you can't find haunter in Black
look in the Pokemon tower in lavender for haunter. note, haunter is hard to find in the Pokemon tower
Haunter can be found on Route 8 or in the Safari Zone.
It attracts a ledendary pokemon.
you get it over a trade.
most likely in any of the higher up caves, or just train a ghastly to level 25, lazyass.
You can find wild haunters in Pokemon tower and lost cave.
curmen cave
this is also for heart gold
you have to use hm rock smash on rocks to find them.
Yes. you can find ghastly at lost tower or Eterna Forest. You can get haunter but i don't know where.
You can't catch a Haunter in Emerald. You can trade for one, you can find a Duskull/Dusclops at MT Pyre, but you can't straight out find a wild Haunter.