This is pretty sweet. You know css “sprites”, where you load one image and restrain it with CSS constraints so that you use the one image in multiple places showing only one section at a time, etc., etc. Well this works in AS3 (i.e. not just in Flex) and it adds some pretty nifty control via CSS. It becomes a sort of way to inject stuff into visual items. Take a look at the (very complete) tutorials listed on the site for examples.
Flash Camo (for short) is a graphics framework that allows AS 3 applications to be easily skinned from pngs, jpgs, or gifs. The framework is broken down into 3 core areas: Decals, the CSS Parser, and the CamoDisplay. When these systems are used together they form a powerful set of tools to help skin and style any Flash application. With Camo’s modular approach, you can use as little or as much of the framework as you want.