First enter the following code into a module of your workbook (or a
module in your Personal.xls to have available to all workbooks):


Sub AssignInsertKey()
Application.OnKey "{INSERT}", "Paste"
End Sub


Sub Paste()
ActiveSheet.Paste
End Sub


Now run just the AssignInsertKey macro. (The AssignInsertKey macro
will automatically initiate the Paste macro.)

Now whenever you do a Copy, all you have to do is hit the Insert Key,
and whatever you copied will be pasted into whatever cell you're in
when you hit Insert