A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
For the Excel instructions go to:
Right-to-left language features -> Set right-to-left text writing -> Microsoft Office Excel 2007
I've got Excel 2010 myself and got the right-to-left layout working just fine (there it's in Options > Advanced), but I checked the above article to see where the options are exactly in 2007.
It now seems to me those instructions weren't properly updated, because the International tab was a feature of Excel 97-2003.
It turns out, the option to change the sheet direction is also on the Advanced tab in Excel 2007, but only if you have installed at least one **RightToLeft** language.
This might also be helpful: How to enable Arabic language support in Windows XP