Usage: ON [#|+|-|^|&|@]MSG [-|^]<parameters> [action]
  This is activated whenever you receive a MSG from someone.
  The parameters for the action are as follows:
    $0    nickname of person who sent the MSG
    $1-   The message

  Warning: If you attempt to send a MSG from within a MSG
  action, it will be automatically converted to a NOTICE, as
  this will prevent MSG loops from being sent between two or
  more users.  Also, you will not be permitted to send either
  MSGs or NOTICEs from within a NOTICE action.  The irc protocol
  states that NOTICEs may not generate automatic replies so this 
  will prevent loops of automatic messages from flooding the net.