Folder Maker Home is a shell extension that will help you to change the color of the icon (or change the icon to some image) which will make them to identify easily.
A handy shell extension that enables you to mark folder icons to indicate a priority level (high, low, normal), level of project completeness (done, half-done, planned), work status (approved, rejected, pending), and type of information stored within (work, important, temp and private files).
Simply right-click on any folder and select the icon or color to be used from the newly added menu option
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This application worth $24.95 but today (April 26, 2010) you can get Folder maker full version license absolutly free from giveaway of the day.
Visit the promotional page here