The FBI seems to be concerned about the DNSChanger Malware that is infecting machines around the world. You might want to visit the site http://www.dcwg.org/ prior to July 9th and test your system or you might lose your internet connectivity. This site has a lot of information about this malware and also provides links to test your system and if infected directs you on how to remove the malware.
The FBI also has a site http://www.fbi.gov/news/stories/2011/november/malware_110911 that discusses DNSChanger.
I would say this is a legitimate concern. I have only tested my machine so far and it tested clean.
on the topic of virus / malware attacks, have you given thought to a
disaster recovery plan? First step is prevention, with trusted
antivirus software. Even more important is a tested backup / recovery
plan. And the final step is a plan that you would follow in the event
of physical disaster, whether it be an office fire, theft of systems,
or hardware failure.
Don't learn the hard way! Give
disaster planning some thought, and if you need any help with this
please contact us to assist you.
Update (May 23, 2012)
You will see that in this article (http://news.cnet.com/8301-1009_3-57439407-83/google-will-alert-users-to-dnschanger-malware-infection/) Google will be warning people that their computer is infected. If you get a notice (see below) on your browser when searching then you will need to follow the directions for removal.