I know this may look simplistic but .....

Code:
  
on *:text:!kill *:#: .describe $chan $2 has been killed


(not tested).

of course "* !kill *" could work if you wanted the "!kill" to appear anywhere on the line.

Cheers,

DK

Darwin_Koala

Junior Brat, In-no-cent(r)(tm) and original source of DK-itis!