Excel 2007

We have a worksheet that is protected. The worksheet contains some unlocked
cells so that people can add data to the file. I've been asked to find a
way to format the cells that require a value so that people who are
unfamiliar with the file will be able to figure it out. Somehow, the tab
named Instructions, which contains full instructions for entering data into
the file, is not sufficient for management. ;-)

Is there a way to conditionally format only cells that are unlocked?

--Tom