I've built on all the advice received to date to construct the following
macro, which changes the header or footer on all charts (special thanks to
Debra Dalgleish for the basis)

footer:
==========================================
Sub ChartFooters()

Dim ws As Worksheet
Dim chObj As ChartObject
Dim ch As Chart

For Each ws In ActiveWorkbook.Worksheets
For Each chObj In ws.ChartObjects
With chObj.Chart.PageSetup
.LeftFooter = "&8" & "Prepared by yourname yourdate"
.RightFooter = "&8" & "Printed &T on &D"
End With
Next chObj
Next ws

For Each ch In ActiveWorkbook.Charts
With ch.PageSetup
.LeftFooter = "&8" & "Prepared by yourname yourdate"
.RightFooter = "&8" & "Printed &T on &D"
End With
Next ch

End Sub
================================================== =

and for the headers
================================================== =



Sub ChartHeaders()

Dim ws As Worksheet
Dim chObj As ChartObject
Dim ch As Chart

For Each ws In ActiveWorkbook.Worksheets
For Each chObj In ws.ChartObjects
With chObj.Chart.PageSetup
.LeftHeader = "&8 " & Application.ActiveWorkbook.FullName
.RightHeader = "&A"
End With
Next chObj
Next ws

For Each ch In ActiveWorkbook.Charts
With ch.PageSetup
.LeftHeader = "&8 " & Application.ActiveWorkbook.FullName
.RightHeader = "&A"
End With
Next ch

End Sub

================================================== ====


Next question: how can I print date in long form (i.e. dddd, mmm dd, yyyy)
in place of &D which returns 04/07/2005?