How To Get Hoho?

You have to help all the kimono girls, then battle them. They'll give you a bell. You will also have needed to beat team rocket in goldenrod's radio tower to get the rainbow wig. Once you have both these items (you should have the necessary badges by this point) you go to the building to the north of the kimono girls dance studio, and the old man lets you enter. Go through the building, and come out on the little path, go to the right, and enter the tower. Ho Oh's at the top.