Need macro to show that workbook has been saved

I have a workbook that I constantly am improving with new macros and VB routines. I sometimes have two versions available for use at the same time. I would like to create a macro or routine that will tell me if the workbook has been saved. A simple cell color change to indicate I've saved would be fine. Also, if I DO save the file and the cell color changes to indicate I have saved, I would like the cell color to change back if any change is made to the workbook. This way I will always know if I need to save or not to keep latest changes. Any suggestions?