i found one! this description is from Manocheese from GameSpot! Here it is:
Anyway, seam walking. There are many "seams" in
OoT. Seams are where two land structures come together and form a sharp angle. You can walk on some of these seams if you are very careful. For example, head to Gerudo Valley from Hyrule Castle. When you are near the Valley, you'll see two rock structures with fences on top. On the right one, there is a seam.
If you keep using C-up, you can slowly walk up this seam and grab the fence at the top. There are many other seams, though, although many of them will just lead you to the void.