Will assume for sake of example that target date is in column A and actual
date in column B, and you have headers (also that you meant for the red cells
you want dates <= today, i.e. past due, not = or ) - then this formula could
be typed in as the first condition for conditional formatting in cell B2:
=(AND(NOT(ISBLANK($A2)),ISBLANK(B2),$A2<=TODAY()))
Set up the format you want for the incomplete tasks due today or before in
the conditional format here (red).
As a second condition add this formula:
=(AND(NOT(ISBLANK($A2)),ISBLANK(B2),$A2<=TODAY()+2 ))
and set up the format for the tasks due within 2 days (yellow).
Then copy cell B2 and then highlight entire column B, paste formats.
Should now highlight any actual date meeting your conditions.

For your conditional format,

" wrote:

Windows XP SP2, MS Excel 2003.

I have a project plan that has target and actual date columns.
Format is 03/02/05.

Would like to highlight the planned date cell if it is within 2 days
of todays date in yellow AND the actual date cell is blank.

If the Actual date is filled in, then no formating of the Planned date
cell.

If the planned date is = or than today and the actual date field is
blank, format the planned date cell RED.

Any help would be greatly appreciated

Thank you