Ho-oh is at Mt.Faraway on the 40th Floor. Ho-oh is pretty strong, to get Mt.Faraway, you have to rescue Latias from Pitfall Valley.When you fight Ho-oh, it is at lvl. 50(I think).Ho-oh should be a easy fight if you have a elec. type pokemon(like Pikachu, I had a Raichu at lvl. 72, right now its at lvl. 86).You'll be lucky enough if Ho-oh joins you on the first try.