After beating the elite 4 you can go to kanto and to pewter city, and go in the poke mart and then someone will give you the rainbow wing. Then after that, go to ecruteak city and go to the building beside the burned tower, and a guard will let you pass. And then after getting through the exit (not the entrance), you will be at the bell tower, enter it but you wont face ho-oh yet. Why? Because there is a gigantic maze inside the bell tower. And it might take a while to get to the top. But when finally get through the maze, ho-oh will be there at the top of the bell tower at lv 70. Now I think that its moves are ANCIENT POWER, PUNISHMENT, SAFEGUARD, and SACRED FIRE. I know. Very powerful, even I havent even beat the elite 4 yet and I don't have ho-oh yet either. But hope all of this helped you.
Laurrren is right arfter you beat the elite 4 you can get in the monk place in ecruteak and there is a puzzle when you get to the end of The puzzle you will find ho-oh even I was shocked I thought you could only get it in heart gold but then I found out how to do the puzzle and I got ho-oh in soul silver!
I do and your 100% right
In Soul Silver you can't get Ho-Oh until you beat the elite four.Unlike in Heart Gold where you get Ho-Oh then have to beat elite four before you can get Lugia.
You have to go to bell tower after you beat the elite 4