This is a snippet taken from a personal addin I named "Project Keeper" and is along the same lines as other replies to this thread. When you create a new workbook and save it for the first time, it simply retains the name given to it. For example, "Book1.xls". All subsequent saves will tag the name with a date and time stamp such as "Book1.092406094329.xls".
<table width="100%" border="1" bgcolor="White" style="filter

rogid:DXImageTransform.Microsoft.Gradient(endColorstr='#C0CFE2', startColorstr='#FFFFFF', gradientType='0');"><tr><TD><font size="2" face=Courier New> <font color="#0000A0">Private</font> <font color="#0000A0">Sub</font> Workbook_BeforeSave(ByVal SaveAsUI <font color="#0000A0">As</font> Boolean, Cancel <font color="#0000A0">As</font> Boolean)
Application.EnableEvents = <font color="#0000A0">False</font>
Cancel = <font color="#0000A0">True</font>
<font color="#0000A0">If</font> Me.FullName = Me.Name <font color="#0000A0">Then</font>
Application.Dialogs(xlDialogSaveWorkbook).Show
<font color="#0000A0">Else</font>
<font color="#0000A0">Dim</font> NewWbName <font color="#0000A0">As</font> <font color="#0000A0">String</font>
NewWbName = Left(Me.Name, InStr(Me.Name, ".")) _
& Format(Now, "MMDDYYHHMMSS.") _
& Right(Me.Name, 3)
Me.SaveAs Replace(Me.FullName, Me.Name, NewWbName)
<font color="#0000A0">End</font> <font color="#0000A0">If</font>
Application.EnableEvents = <font color="#0000A0">True</font>
<font color="#0000A0">End</font> <font color="#0000A0">Sub</font>
</FONT></td></tr></table><button onclick='document.all("925200603912980").value=document.all("925200603912980").value.replace(/<br \/>\s\s/g,"");document.all("925200603912980").value=document.all("925200603912980").value.replace(/<br \/>/g,"");window.clipboardData.setData("Text",document.all("925200603912980").value);'>Copy to Clipboard</BUTTON><textarea style="position:absolute;visibility:hidden" name="925200603912980" wrap="virtual">
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
Application.EnableEvents = False
Cancel = True
If Me.FullName = Me.Name Then
Application.Dialogs(xlDialogSaveWorkbook).Show
Else
Dim NewWbName As String
NewWbName = Left(Me.Name, InStr(Me.Name, ".")) _
& Format(Now, "MMDDYYHHMMSS.") _
& Right(Me.Name, 3)
Me.SaveAs Replace(Me.FullName, Me.Name, NewWbName)
End If
Application.EnableEvents = True
End Sub</textarea>