macos - Switch the keys caps lock and shift

Is there a way to switch the shift key with the capslock key?

I have a problem with the shift keys, and I would like to use the caps lock keys, instead of the left shift key.
Mac OS X settings allow to modify the keys used for some modifiers, but it doesnt't allow to change the key used for the shift key, nor to select the shift keys as alternative key for another modifier.

Answer

I found http://pqrs.org/macosx/keyremap4macbook/, which allows, in example, to swap fn with left shift (it actually allows to remap fn to left shift, and left shift to fn, among other things).