Okay, here's how I do it (with somewhat different words--I copied these from the DT):

  Verse:
       Am                 Am          
  Some friends and I in a public house 
       Am                   Am        
  Were playing dominoes one night 
       Am       Dm     Am      Dm     
  When into the room a fireman came, 
      Dm       Dm     E            
  His face all chalky white 
          Am                Am
  "What's up?" says Brown, "Have you seen a ghost?" 
   Am                        Am        
  "Have you seen your Aunt Moriah?"
         Am      Dm     Am              Dm  
  "Oh my Aunt Moriah be buggered," says he, 
       E                E                 
  "The bleeding pubs on fire" 
  
  Chorus:
      Am               Am             
  Oh, there was Brown, up side down 
  Am                            Am     
  Mopping up the whiskey on the floor 
   Am     Dm         Am      Dm     
  "Booze, booze" the firemen cried 
     Dm          Dm              E        
   As they come a knockin' at the door 
        Am                        Am            
  "Well don't let em in till it's all mopped up 
  Am                      E              
  Somebody shouted, "MacIntyre" 
         Am      Dm         Am        Dm    
  And we all got blue blind paralytic drunk 
           E                  E         
  When the Old Dun Cow caught fire 
  
  (Last line:)
           E                  Am      
  When the Old Dun Cow caught fire