Try the following macro:
'jcz - 24.04.06
'
Sub HighlightToBlack()
Dim oRange As Object
Set oRange = ActiveDocument.Range(Start:=0, End:=0)
Application.Options.DefaultHighlightColorIndex = wdBlack
With oRange.Find
.ClearFormatting
.Highlight = True
With .Replacement
.ClearFormatting
.Highlight = True
End With
.Execute Replace:=wdReplaceAll, Forward:=True, FindText:="", _
ReplaceWith:="", Format:=True
End With
End Sub
Hope it helps. Although I have tested it on Word 2000 it should work as
well in 2003, I hope.