If you select one of the cells that are formatted and click Format and select Conditional Formatting (Windows XP) you will see the conditions that I put in.

Basically you are formatting the cell so that if the contents are < than TODAY() you want the background colour to be red.

Then you add a second condition which says if the contents of the cell are less that TODAY()+30 you want the background colour to be orange.

Not sure where this sits in Office 2007 or 2010.

Glad to be able to help.