Something like this:-
vb Code:
  1. Private Sub ChangeFont(ByVal F As Font)
  2.  
  3.         For Each C As Control In Me.Controls
  4.             C.Font = F
  5.         Next
  6.  
  7.     End Sub
That function would work on forms, usercontrols and controls. If you plan on putting a function like that into a module or any class that is not a container you could do it like this:-
vb Code:
  1. Private Sub ChangeFont(ByVal ContainerCtl As Control, ByVal F As Font)
  2.  
  3.         For Each C As Control In ContainerCtl.Controls
  4.             C.Font = F
  5.         Next
  6.  
  7.     End Sub
ContainerCtl would be the object where all the objects who's fonts you wish to change are situated.