From: ard at p850ug1.demon.co.uk 
---snip---
  Is there a simple way to find shorted caps
in-circuit? Would an absolutely 0
 ohm resistance while in-circuit indicate a shorted cap for the reason I
 suggest above? 
 There's no simple way, it's easier just ot desolder at least one end and
 test them effectively out-of-circuit.
 The fact that you've found something that's shorted that shouldn't be is
 a clue I think. What does that capacitor connect to (it may be easier to
 trace this o nthe good PCB where the 2 ends don't test as being shorted
 together).
 -tony 
 
Hi
 With the correct equipment, the method I spoke of works
quite well. I've never failed to locate the short and within
5 minutes. No damage to the board or components that
could occur by unsoldering parts until the shorted one is
found.
Dwight