Mac OS X Lion introduced a new feature where in many applications you can press (Command-Control-D) to produce a popup with the definition for the word under the mouse cursor. A side effect of this is that you can no longer use the same shortcut to access functionality in other applications (for example, Emacs).
Is it possible to either
a) disable the word definition Command-Control-D keyboard shortcut, or
b) change the word definition keyboard shortcut to something other than Command-Control-D?