For those who much prefer classic labels to the garish X versions, and have been waiting interminably for Unsanity to update Labels X, iconXprit could be the answer. It can colorize icons from a custom list or any free colour via a contextual menu.

In fact, though it takes a bit more setting up, iconXprit exceeds the capabilities of Labels X in several important respects: colours can be mapped to keyboard shortcuts, there is no seven colour limit, and you can still use Finder labels alongside icon colours (for those occasions when an in-your-face banner is what you really want).

And colorizing icons is only a part of what iconXprit can do: it can also apply text, copy and paste custom icons, apply from an archive, and more.

Early versions were a bit buggy, but the current version seems stable enough for me (G5, Leopard)—and it does not use APE.