We noticed a few articles about this just today. Apparently the FBI took down servers by international criminals who had infected millions of computers with a DNS Changer for an online advertising scam that netted the criminals millions.
The FBI put up DNS servers to replace those setup by the criminal. However, these FBI servers will be brought down July 9, 2012 and an estimated 350,000 will no longer be able to resolve DNS on their infected computers.
They suggest “To check and clean computers, try: www.dcwg.org”
See:
http://www.fbi.gov/news/stories/2011/november/malware_110911
http://abcnews.go.com/Technology/wireStory/hundreds-thousands-lose-internet-july-16184005
http://www.kgw.com/news/business/Many-may-lose-Internet-in-July-when-FBI-shuts-down-virus-screen-148307275.html