I want edit an existing minecraft texture pack, how?

I want to edit this texture pack http://www.minecraftdl.com/faithful-64x64-texture-pack/

and its really good but i don't like the cobblestone. Is there a way to pull the cobblestone texture off of this texture pack http://www.minecrafttexturepacks.com/runescape-pack/?

a step by step guide would be great, thanks

What you need to do is download the texture pack itself, then extract it and double click it to look in its files. You'll find a file for the cobblestone texture, which you can remove, or replace. Then all you'd have to do is make sure the new texture has the same name as the old and is located in the same file, or go into the settings.cfg file and look for the cobblestone code and change the name of the old texture to the new texture that you added.