You need to use superscript chiropractors. When I type cm² the 2 is not type
from the keyboard and then formatted, rather I hold the ALT key and on the
number pad type 0178. Similarly, 0179 gives cm³.
The fonts in Office 2007 (Calibri and Cambria) have characters for the other
digits which are accessible from the Insert Symbol dialog
If you need a font with these super- and subscript digits, visit
http://people.stfx.ca/bliengme/ExcelTips/Exponents_in_Cells_and_Charts.htm
where there is a link to such a font. This font has an added benefit
compared to the new MS fonts in that the ANSI codes for 0 thru 9 are
sequential
best wishes