I wish that the "label" feature in Finder would change the colors of the folders, rather than put a big bubble around the text.
Until that happens, here is a set of folder icons colored to match the labels. Unfortunately these icons don't open as you drag stuff into them (any advice on how to do this?)
You Get (for each color):
An application that does nothing (and only in Mac OS X) to transfer the icon from.
An .icns file
PNGs for each size