Symantec posted on their site the latest information on the next chapter of Stuxnet. The site says that "Duqu" is a new threat whose goal is to gather intelligence in order to conduct a future Stuxnet-like attack.
Duqu has nearly identical parts to Stuxnet, but it has a completely different purpose. Its purpose is to gather intelligence and assets like design documents that will give the attackers the insights they need to mount a future, highly-targeted attack on organizations such as industrial control facilities.
Learn more about Duqu at Symantec's site http://www.symantec.com/business/outbreak/?id=stuxnet&inid=us_ghp_banner1_duqu