if you want to change your keyboard sound you will need to find this directory on your phone (via SSH):
system/library/audio/UIsounds
from there you will need to change the Tock.caf to whatever you want the sound to be, make sure that everything is spelled exactly the same as the file you see.
or if you have winterboard installed and you don't want to replace the original file, then first create a folder (name it wahtever you like) and inside that folder create another called UIsounds. so it might be Custom Keyboard Sound/UIsounds then you will want to go here on your phone (via SSH):
Library/Themes/Custom Keyboard Sound/UIsounds place your Tock.caf file in there and enable your theme, respring.
then you will have a custom keyboard sound for your iphone.
**NOTE** files and file folders must be named exactly as they are seen on your phone, if the folder has uppercase letters you have to match that, same with the files you are intending on "overwriting" with winterboard **NOTE**
