jvmn,
Your title says to change the color once over a year but the post says
to change the date? To change the color use Conditional Formatting.
Format>Conditional Formating
Change Cell Value Is option to Formula is. Use this in A1 (or where
your dates begin).
=DATEDIF(A1,TODAY(),"y")>0
Click on Format, Patterns and choose a color. Click OK and OK. You
can then copy this format to the rest of your range using either Past
Special - Formats or using the Format Painter. I believe that you'll
need to install the Analysis ToolPak to use this formula. To do so go
to Tools>Add-ins and check off the analysis toolpak option. Click ok.
Does that help?
Steve