You can use a macro:
Put this in your workbook's ThisWorkbook code module (if you're
unfamiliar with macros, see David McRitchie's "Getting Started with
Macros":
http://www.mvps.org/dmcritchie/excel/getstarted.htm
for help):
Private Sub Workbook_BeforePrint(Cancel As Boolean)
Dim wsSheet As Worksheet
For Each wsSheet In ActiveWindow.SelectedSheets
wsSheet.PageSetup.LeftHeader = Format(Date, "dd mmm yyyy")
Next wsSheet
End Sub
Substitute CenterHeader, RIghtHeader, LeftFooter, etc. as desired (as
well as changing the date format string).
