This page was written by Harald Staff, and is included here with his kind permission. A pivot table is a great reporting tool that sorts and sums independent of the original data layout in the spreadsheet. If you never used one, this demo may be of interest. Now choose any cell in this table and choose Pivot Table wizard in the Data menu. Excel asks for the data source and suggests this table.
Next question is the data range.
Excel suggests the table. If you expect to add data in the future, set the data range to include as many rows as you think you will ever need. Now comes the layout wizard, show below. What into the ROW area, and the Amount header into the Data area. Finally Excel asks if the table should be placed in a new worksheet.