Yesterday I got a question about the unit system in Excel. Andy from down under wrote:

I am not a huge user of all the complex stuff that excel does but your ASAP has made my work easier.
Simple thing like changing case when I've left the caps lock on!!
I do have a question for you.
Is it possible to set margins, columns and rows in centimetres??

If you want to set margins etc. in centimeters you have to change your country settings in windows, it is not a separate options in Excel.
In Windows (XP): start » setttings » control panel » Regional and language options then click on the "customize" button and change the measurement system to metric.

You have to restart Excel for this to take effect.