Hi Guy

If you want it to work in all your workbooks, you better change it to
an add-in.
I never did that though, but at least i can try:

For that, open a new workbook
hit alt+F11
Insert - Module.
(Change the name of the Module in the properties window, if you want)
Paste the Macro in this module
Open the Worksheet in the VBA-editor
(if you don't see it press Ctrl+R)
Insert following code:
'-------------------------------------------------------------------------------------------------
Private Sub Workbook_AddinInstall()

Dim cMenu1 As CommandBarControl
Dim cbMainMenuBar As CommandBar
Dim iHelpMenu As Integer
Dim cbcCutomMenu As CommandBarControl

On Error Resume Next

Application.CommandBars("Worksheet Menu Bar").Controls("My
Tools").Delete

On Error GoTo 0

Set cbMainMenuBar = Application.CommandBars("Worksheet Menu Bar")
For Each mb In Application.CommandBars(1).Controls
If mb.ID = 30010 Then
iHelpMenu = mb.Index
Exit For
End If
Next mb

Set cbcCutomMenu = cbMainMenuBar.Controls.Add(Type:=msoControlPopup,
Befo=iHelpMenu)
cbcCutomMenu.Caption = "My Tools"

With cbcCutomMenu.Controls.Add(Type:=msoControlButton)
.Caption = "Insert rows in Column A"
.OnAction = "ins_rows"
End With

End Sub

Private Sub Workbook_AddinUninstall()

On Error Resume Next
Application.CommandBars("Worksheet Menu Bar").Controls("My
Tools").Delete

End Sub
'-------------------------------------------------------------------------------------------------
close the vba-editor

save the excel sheet as .xla
(it should automatically be saved to your add-in folder)

Close Excel and open a new worksheet.
Tools - Add-Ins
and you should see your add-in in the list
(the name with which you saved it without .xla)

hope that helps, please test it and give feedback as it is my
first try with add-ins.

if you want to have additional infos, check google, there
are some great tutorials like that from ozgrid:
http://www.ozgrid.com/VBA/excel-add-in-create.htm

that takes care of your question 1 and 2.

now to question 3:
it's a fairly simple code, which checks if the value
of this rows cell in column A is like the one stored in
var_before. To read it more easily copy the whole
code and paste it into the VBA-editor.
'---------------------------------------------------------------------------------
Sub ins_rows()

Dim var_before As Variant
'set var_before to cell A1 (row 1, column 1)
'Cells(1,1).value means the value of Cell A1
var_before = Cells(1, 1).Value

For i = 1 To 65536
'this function will only go as far as the first
'blank cell in column A
If Cells(i, 1).Value = "" Then
Exit For
End If
'if the cell value is not the same as the one
'stored in var_before do following:
If var_before < Cells(i, 1).Value Then
'set var_before = cell value so that the next
'comparison will be accurate
var_before = Cells(i, 1).Value
'insert 1 row where the row(i) is right now,
'move all the other rows down.
Rows(i).Insert Shift:=xlDown
'jump over one line, because we inserted one
i = i + 1
End If

Next i

End Sub
'---------------------------------------------------------------------------------

if there are any other questions, just ask

Cheers Carlo