To at least Excel 2000, if you have the Tools, Options, Comment Indicator Only
you will see the comment if you hover over the cell with the mouse. You will not
see the comment if you arrow key into the cell to select the cell.
I think some of this behavior was changed in Excel 2003 so that you have
to select the cell. . In any case the difference
between having the comment show as you hover as opposed to having
to select the cell is not something you can override.
Along the lines of editing the comment to see it, you can use a right click
(context menu) to edit the cell comment, which is probably easier since you
probably already would be using the mouse.