Anyway, here's what I have done so far. Launch it from the Tools menu at the top of Excel.
Push the little "plus" button to change the Watch Cell (the cell to be watched, just like the Watch Window toolbar, but far more simpler)
The Cell Watch userform pops up showing the active cell's column, row and active sheet. Use the dropdown lists to set yourself withing the activeworkbook and then push one of these four buttons.
The active book and sheet you choose will be recorded. Now depending on the choice you made, you can select another sheet or book and far right caption of the toolbar will change accordingly.
Let's say you selected, "Column" with the active cell in D. No matter which cell you select in whichever sheet or book, the value shown in D for the corresponding row in the recorded sheet and book will show in the toolbar. So selecting J7 will cause the toolbar to show the value in D7 of the recorded sheet and book. Keep in mind you can use this to show values in hidden rows and columns too, use the dropdown lists to select them.
Row works the same way as Column but this time the row is fixed (plus the sheet and book) Of course, there is nothing to stop you from using the same sheet and/or book as recorded. A possible workaround when you can't see headings at the top? An alternative to freezing panes?
Sheet shows value of the cell that corresponds with the fixed sheet and book (same cell address).
Fixed makes everything static, always the same cell in the same sheet and book. But it might come in hand to make sure a certain cell has not changed according to something you just entered.
Hover the cursor over the caption to see the option you have chosen, the watch cell path and address, then it's formula and format. (This is a litte buggy at times but is handy when okay)
Two more things. Push the button with the "pencil" icon, you can enter text of your choice into the caption. Push it again and it changes back to normal.
And finally, push the watch cell caption itself to enter it's value into the clipboard. Just the thing when you want to paste somewhere else, even a different program like Word or Outlook. Have fun.
Plans exist to make a better version when I have time, the current download link is here.
Speaking of improvements, I did make a change to New Book Navigator. You can enter your own names for the Highlight shapes using an input box. This means you can select a different group of cells and name all of them "May Sales, 2006". Then when it comes time to remove them, enter the same name and only those highlight shapes will be removed. Very convenient, there's more stuff coming up for this addin too. Get the latest version here.