How do you change measurement units of margin in Excel 2003?

[JV]

My Window XP-regional-setting's measurement unit is already set at cm.

[wjohnson]

From the EXCEL HELP MENU
Unlike Microsoft Word, Excel does not provide a horizontal or vertical ruler, and there is no quick way to measure the width or height of a worksheet in inches. Excel uses characters, points, and pixels as units of measurement.

The width of cells is displayed in characters and pixels rather than in inches. When you drag the boundary of a column heading to adjust the width of a column on the worksheet, a ScreenTip displays the width in characters and shows pixels in parentheses.
The height of cells is displayed in points and pixels rather than in inches. When you drag the boundary of a row heading to adjust the height of a row on the worksheet, a ScreenTip displays the height in points and shows pixels in parentheses.
An approximate conversion of points and pixels to inches is shown in the following table.

Points Pixels Inches
18 24 .25
36 48 .5
72 96 1
108 144 1.5
144 192 2