There is a very interesting worm going around the world right now which is specifically targeting industrial control systems. According to Business Week, the worm is targeting a Siemens plant control system, probably with the intent to steal production secrets and maybe even information useful to create counterfeit products. This is the first instance I have seen of malware targeting the area of embedded systems. However, the actual systems targeted are not really embedded systems, but rather regular PCs running supervision and control software.