Is there something you are missing or another method where both 2003 and 2007 can use the same color coding methods either using colored flags or colored categories?
Outlook 2003 Colored Flags were migrated to Color Categories in Outlook 2007. There is no link in how Color Categories in Outlook 2007 are downgraded to Color Flags in Outlook 2003. This would be impossible as well considering the fact that there are many more colors to choose from in Outlook 2007 than in Outlook 2003.
However, the Categories assigned in Outlook 2007 are still assigned in Outlook 2003; they are just missing a color. You can define an Automatic Formatting rule in your view in Outlook 2003 to color the header text based in the message list based on which category is assigned.
1. click on “View” under menu and the click “Arrange By-” and then select“Custom”
3. First add the Name of the rule
4. Press “Font” to select a font and other font properties
5. Press Condition and Select the More Choices tab
6. Press the “Categories” button to select one or more categories that you want to show up in that font setting
7. Press OK and Move the rule if needed (the last rule that applies wins when there are font conflicting settings)also create additional rules if needed