I don't think so.
Since changing a comment (cell note) doesn't generate an event you
can't even write a program to update the other cell with the comment
automatically.

You could use a visual basic function to extract the text from the cell
note and show it in a cell in the other worksheet though.  Add this VBA
function in a standard module in the VBProject of the workbook you want
to contain the formula.

Function GetComment(R As Range) As String
 Application.Volatile
 If R.Comment Is Nothing Then Exit Function
 GetComment = R.Comment.Text
End Function

In the cell you want the copy of the comment to appear in,

=GetComment([OtherBook.xls]Sheet1!$A$1)
(adjusting the address appropriately)

For best results format the cell to wrap text.

Bill Manville
MVP - Microsoft Excel, Oxford, England
No email replies please - respond to newsgroup