You can find Hoothoot on: Routes 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 43, 47 and 48, Ilex Forest, New Bark Town, Cherrygrove City, Violet City, Ecruteak City, National Park, and the Safari Zone.
I started two days ago and I saw a lot of hoothoots in the first few grass patches. They suck though.
You can find hoothoot in rt. 29 in the evening. You will find them at a low level.
http://www.serebii.net/pokedex/163.shtml
It attracts a ledendary pokemon.
Level 94 But must have the skills earthquake & zap cannon
curmen cave
this is also for heart gold
evolve gastly.
you have to use hm rock smash on rocks to find them.
You can find them by surfing and fishing.
It's Darkrai. You can't get him in Heart Gold.
pokemon heart gold
Well I do have the game. I did see suicune in it.